Electric generator inspection system and motor controller

An inspection system inspects the interior of the stator of an electric generator for the existence of several problems. The inspection apparatus is mounted on a carriage that travels along the slots defined by the stator. An indexer is mounted to the rotor of the generator and can travel around the circumference of the rotor to deliver the carriage to the desired slot. An indexer plate is mounted to the indexer and can be registered with the desired slot to insure that the carriage can enter the slot from the indexer. An associated motor controller disables the motor if an electrical fault is disclosed.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
The present invention pertains to a remote inspection of electric 
generators without disassembly, and a motor controller, and particularly 
to an automatic inspection system. 
2. Description of the Prior Art 
Two major problems commonly develop in the stator of electric generators 
after they have been in operation for some time. First, the insulation 
between stator laminations can break down. Second, the stator coil wedges, 
which are located within the slots defined by the stator and prevent the 
stator coils from vibrating, can become loose. Further, miscellaneous 
problems that can be detected visually can occur within the stator. 
Tests have been developed to determine the existence of the problems 
described above. However, such tests are conducted manually and require 
removal of the rotor from within the stator. Rotor removal is a long and 
involved process. Removing the rotor, manually performing the test, and 
replacing the rotor can often consume ten to fourteen days. Removing the 
generator from service for such a period imposes serious problems on those 
relying on operation of the generator. Further, removing the rotor from 
the stator can itself cause damage to the stator. Also, replacing the 
rotor can damage the stator and a stator that has passed inspection may in 
fact be defective after rotor replacement has damaged the stator. 
Accordingly, there exists a need for an inspection system for an electric 
generator that does not require removal of the rotor from within the 
stator to perform the inspection. 
SUMMARY OF THE INVENTION 
The present invention provides a system for inspecting an electric 
generator. The system includes apparatus for inspecting and providing 
information pertaining to the tightness of the stator coil wedges of the 
generator. The system also includes apparatus for inspecting and providing 
information pertaining to the electrical integrity of the stator 
lamination insulation. The system further includes apparatus for visually 
and remotely inspecting the interior of the surfaces of the stator and the 
rotor of the generator. The system includes apparatus for delivering each 
inspecting apparatus to the site of inspection and for retrieving the 
apparatus therefrom. The system also includes apparatus for causing each 
inspection apparatus to conduct an inspection at an inspection site. 
The present invention provides a further inspection system for an electric 
generator. The system includes apparatus for inspecting and providing 
information pertaining to the tightness of the stator coil wedges of the 
generator. The system further includes apparatus for delivering the 
inspection apparatus to the site of inspection and for retrieving the 
inspection apparatus therefrom. The system also includes apparatus for 
causing the inspection apparatus to conduct an inspection at an inspection 
site. 
The present invention provides a further inspection system for an electric 
generator. The system includes apparatus for inspecting and providing 
information pertaining to the electrical integrity of the stator 
lamination insulation of the generator. The system also includes apparatus 
for delivering the inspection apparatus to the site of inspection and for 
retrieving the inspection apparatus therefrom. The system also includes 
apparatus for causing the inspection apparatus to conduct an inspection at 
an inspection site. 
The present invention provides a further inspection system for an electric 
generator. The system includes an apparatus for visually and remotely 
inspecting the interior surfaces of the stator and of the outer surface of 
the rotor of the generator. The system includes apparatus for delivering 
the inspection apparatus to the site of inspection and for retrieving the 
apparatus therefrom. The system further includes apparatus for causing the 
inspection apparatus to conduct an inspection at an inspection site. 
The present invention provides a further inspection system for an electric 
generator. The system includes a carriage adapted to travel along the 
slots defined by the stator of the generator. Apparatus is mounted on the 
carriage for inspecting and providing information pertaining to the 
tightness of the stator coil wedges of the generator. Apparatus is 
provided for moving the carriage along the stator slots to sites of 
inspection. An indexer is adapted to be releasably secured to the rotor of 
the generator. The carriage and the indexer are adapted to permit the 
carriage to be received and retained by the indexer when the carriage 
exits a slot. Apparatus is provided for aligning the indexer with each 
slot to permit the carriage to enter the slot when the carriage travels 
out of retention of the indexer. Apparatus is provided for moving the 
indexer around the circumference of the rotor to deliver the carriage to a 
desired slot. Apparatus is provided for causing the inspection apparatus 
to conduct an inspection at an inspection site. 
The present invention provides a further 5 inspection system for an 
electric generator. The system includes a carriage adapted to travel along 
the slots defined by the stator of the generator. Apparatus is mounted on 
the carriage for inspecting and providing information pertaining to the 
electrical integrity of the stator lamination insulation. 
Apparatus is provided for moving the carriage along the stator slots to 
sites of inspection. An indexer is adapted to be releasably secured to the 
rotor of the generator. The carriage and the indexer are adapted to permit 
the carriage to be received and retained by the indexer when the carriage 
exits a slot. 
Apparatus is provided for aligning the indexer with each slot to permit the 
carriage to enter the slot when the carriage travels out of retention of 
the indexer. Apparatus is provided for moving the indexer around the 
circumference of the rotor to deliver the carriage to a desired slot. 
Apparatus is provided for causing the inspection apparatus to conduct an 
inspection at an inspection site. 
The present invention provides a further inspection system for an electric 
generator. The system includes a carriage adapted to travel along the 
slots defined by the stator of the generator. Apparatus is mounted on the 
carriage for visually and remotely inspecting the interior surfaces of the 
stator and of the rotor of the generator. Apparatus is provided for moving 
the carriage along the stator slots to sites of inspection. An indexer is 
adapted to be releasably secured to the rotor of the generator. The 
carriage and the indexer are adapted to permit the carriage to be received 
and retained by the indexer when the carriage exits a slot. 
Apparatus is provided for aligning the indexer with each slot to permit the 
carriage to enter the slot when the carriage travels out of retention of 
the indexer. Apparatus is provided for moving the indexer around the 
circumference of the rotor to deliver the carriage to a desired slot. 
Apparatus is provided for causing the inspection apparatus to conduct an 
inspection at an inspection site. 
The present invention provides a further inspection system for an electric 
generator. The system includes a carriage adapted to travel along the 
slots defined by the stator of the generator. Apparatus is mounted on the 
carriage for inspecting and providing information pertaining to the 
tightness of the stator coil wedges of the generator and the electrical 
integrity of the stator lamination insulation and for visually and 
remotely inspecting the interior surfaces of the stator. Apparatus is 
provided for moving the carriage along the stator slots to sites of 
inspection. An indexer is adapted to be releasably secured to the rotor of 
the generator. The carriage and the indexer are adapted to permit the 
carriage to be received and retained by the indexer when the carriage 
exits a slot. 
Apparatus is provided for aligning the indexer with each slot to permit the 
carriage to enter the slot when the carriage travels out of retention of 
the indexer. Apparatus is provided for moving the indexer around the 
circumference of the rotor to deliver the carriage to a desired slot. 
Apparatus is provided for causing the inspection apparatus to conduct an 
inspection at an inspection site. 
The present invention further provides a motor controller. The controller 
includes a source of energizing power for the motor and a pulse width 
modulator for controlling application of the power source to the motor. 
The modulator includes a transistor H-bridge. The controller also includes 
apparatus for detecting an electrical fault in the motor, for disabling 
the motor upon occurrence of the fault, and for preventing the motor from 
being restarted until a reset switch is actuated. Preferably, the 
controller includes apparatus for limiting the maximum current that can 
flow into the motor. Also, preferably, the controller determines that a 
fault exists when the currents entering and exiting the motor are not 
substantially equal to each other.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
FIG. 1 shows a generator inspection assembly that is used to remotely 
inspect the stator of an electric generator. The inspection assembly 
includes, generally, a carriage assembly, an indexer plate, and an 
indexer. The carriage includes inspection apparatus and is adapted to 
travel along the stator. The indexer is adapted to move around the rotor 
to deliver the carriage to a desired slot of the stator. The indexer plate 
is adapted to move somewhat and provides positive registration between the 
indexer and the slot. A computer and video system permits electrical and 
visual data generated by the generator inspection to be recorded for 
real-time or post-inspection analysis. 
The carriage contains several subassemblies that perform inspection or 
testing and that move the carriage assembly within the stator of a 
generator. The teeth that make up some generators contain two sets of 
grooves. In those generators, a bottom set receives wedges that retain 
stator coils in the slots between the teeth and prevents them from 
vibrating. A top set permits the carriage to travel along the length of 
the stator teeth on wheels attached to the top of the carriage. As the 
carriage travels the length of the generator on the top set of stator 
teeth slots, or grooves, inspection of the stator is accomplished. The 
location of the carriage within the generator is continuously monitored to 
permit the operator to know the exact location of any portion of the 
stator that is damaged. 
The carriage is housed prior to generator testing in the indexer plate. The 
indexer plate, which is housed within the indexer, positions the carriage 
at the active end of the generator such that the drive wheels of the 
carriage are aligned between the top set of grooves on the stator teeth. 
The indexer plate and carriage assemblies rotate around the rotor on the 
indexer assembly. 
The indexer travels on chains which traverse the circumference of the rotor 
retaining ring. The chains are wrapped around the rotor retaining ring 
only when generator testing is being performed. The indexer, which is 
computer controlled, travels on the chains, stopping at every slot that is 
to be tested. 
When generator inspecting is desired, the upper bearing bracket on the 
generator housing is removed and a belt is wrapped and secured around the 
rotor retaining ring. The belt provides tracks which permit the chains to 
remain parallel to each other so the indexer does not jam as it travels 
around the rotor. The belt is secured to the rotor retaining ring by 
passing strips of material over the belt and fastening the ends together 
with a conventional fastening device sold under the trademark "VELCRO". 
Once the belt is secured to the rotor retaining ring, chains are placed in 
the tracks on the belt. The indexer is mounted to the belt and the chains 
are threaded through the indexer on gears attached to the indexer. The 
ends of each chain are fastened together with a clasp. 
Once the indexer is installed on the rotor retaining ring, the indexer 
plate is mounted to the indexer. Prior to mounting the indexer plate to 
the indexer, the carriage is slid into the indexer plate, with the end 
containing the camera positioned toward the generator, that is, the camera 
confronts the generator. Various electrical and video connections are made 
to the carriage and indexer. The indexer plate is adjusted to a level 
alignment plane using jack screws such that the carriage will be in proper 
position to travel down the top tracks of the stator 0 teeth and perform 
the necessary inspections. The alignment of the carriage in the indexer 
plate is accomplished by placing the drive wheels of the carriage in a 
grooved section of the indexer plate Once the indexer plate, with its 
carriage assembly, is attached to the indexer, the inspection can begin. 
The indexer is positioned, by the operator and the computer, to the first 
slot to be tested Once the indexer is positioned, the indexer plate is 
driven by a motor along the indexer until registration with the stator is 
achieved. To prevent indexer plate contact with the stator, non-contact 
proximity sensors are employed to determine when the end of the indexer 
plate just enters the slot. When the indexer plate is in registration with 
the slot, the carriage is aligned properly with the slot. A signal is sent 
to the computer indicating proper alignment. The operator commands the 
computer to move the carriage, and the computer generates a signal that 
causes the carriage to move out of the indexer plate and into the top 
stator slot grooves, driven by the carriage drive wheels. Inspection of 
the stator takes place once the carriage is disposed within the stator 
teeth. 
Three inspections are performed within the stator slots. A visual 
inspection is performed by the camera assembly. A stator lamination 
insulation integrity test is performed by the lamination integrity ("LI") 
assembly. A wedge tightness test is performed by the wedge tightness 
("WT") assembly Visual inspection is done to determine whether there are 
any problems of a gross nature existing within the generator. A mirror 
assembly is connected to a camera such that the entire interior of the 
stator slot and of the rotor can be visually scanned. A video signal is 
sent back to the computer and video system to permit real-time and 
post-inspection analysis. The lamination integrity ("LI") inspection may 
be performed at the same time the visual inspection takes place. 
Detectors, known to those skilled in the art as "ELCID" detectors, a 
trademark of the Central Generation Electrical Board of Great Britain and 
manufactured by Adwel Industries, Limited, Ruislip, London, England, 
measure fault currents which are generated when there is a breakdown of 
insulation between two or more adjacent laminates that make up the teeth 
of the stator. 
The wedge tightness ("WT") inspection determines whether the stator coil 
wedges remain wedged sufficiently tightly within the stator slots. When 
the stator coils are mounted in the slots of the stator, they are secured 
in place with a wedge plate, which fits in the bottom set of slots of the 
stator teeth. The wedge must be tight to prevent slippage or vibration of 
the stator coil during generator use. The WT inspection checks for a loose 
wedge by impacting the wedge and recording and analyzing the acoustic 
signal produced by the impact. 
The WT assembly is delivered by the carriage to any desired location within 
the stator. To perform the inspection process, the WT is raised into 
positions and held by a constant current motor/circuit. A solenoid powered 
impactor is actuated to strike the wedge several times. Following this 
sequence, the data is collected by the FGI Computer System and the WT is 
lowered to its normal home position. The data is acquired in two modes, 
Acoustic Waveform and Zero-Slope. 
The Acoustic Waveform is amplified and sampled by an A/D converter at a 50 
KH.sub.z rate. 128 points are collected during each sequence. Then, the 
first seven zero-slope positions along the acoustic waveform are detected 
and marked. The elapsed time between each of the seven zero-slope 
positions is measured and recorded. This process is repeated for each test 
position along the wedge resulting in a matrix of strikes vs. zero-slope 
values. The high and low values in each column are discarded. The 
remaining values in each column are used to derive an adjusted average. 
This adjusted average has been experimentally proven to be inversely 
proportional to wedge tightness. 
An encoder wheel on the carriage permits displaying for the operator the 
exact position of the carriage when it is engaged with the stator. Knowing 
the location of the carriage permits the operator to pinpoint problem 
areas without having to remove the rotor from the generator. 
Although a detailed description of the inspection processes is provided 
during the discussion of the computer systems that controls the inspection 
apparatus, a general description of each inspection procedure is provided 
at this point. The LI inspection is conducted by the operator by moving 
the indexer around the rotor to the desired stator slot. When the desired 
stator slot has been reached by the indexer, the operator causes the 
indexer plate to move outward from the indexer until indexer plate 
registration with the stator slot is achieved. 
Non-contact proximity sensors on the indexer plate are provided to permit a 
determination of registration to be made. When the indexer plate is in 
registration with the slot, the operator moves the carriage out of the 
indexer plate and into the stator slot. When the LI assembly, located on 
the carriage, reaches the inspection site, the carriage is stopped and the 
LI assembly is raised until it contacts the stator. The LI assembly 
includes ferrite plugs which actually contact the stator. Once contact 
with the ferrite plugs is achieved, the carriage is moved along the slot 
and lamination integrity data is gathered by the LI coils of the LI 
assembly and processed and displayed. At the end of the scan, the carriage 
can be returned to its home position, that is, the position in which it is 
located on the indexer plate. 
The WT inspection is initiated by moving the indexer and indexer plate as 
described with reference to the LI inspection described above. The 
carriage is moved along the slot to the desired wedge, and the WT assembly 
is moved along the inspection site on the wedge. The WT assembly is raised 
to bring the impact of the assembly into a position where it can impact 
the wedge. The computer energizes the solenoid of the WT assembly which 
causes the impactor to strike the wedge. The wedge is struck several times 
and an acoustic sensor on the WT assembly gathers acoustic data generated 
by those impacts. The signal is conditioned by a conditioning circuit and 
transmitted to the computer for processing and display. 
The camera assembly permits the operator to visually and remotely inspect 
the stator slots and the rotor for problems of a gross nature and to aid 
in positioning the carriage within the stator. The camera includes a lens 
that can be moved by the computer to adjust the focus of the camera. The 
camera assembly includes a mirror that can be both rotated and tilted to 
permit viewing of the entire interior of the stator slot and of the rotor 
by the operator. 
The details of the generator inspection assembly shown in FIG. 1 are 
presented below. 
FIG. 1 shows a perspective view of generator 20 and computer and video 
system 22. Carriage 62 is shown engaged with teeth 28 of stator 32. Coil 
30 is mounted between stator teeth 28, which is constructed from teeth 
laminates 26. Indexer 58 rides on chains 68 and causes indexer plate 
assembly 60, which acts as a housing for carriage 62 when carriage 62 is 
in its home, or passive, position, to travel around the circumference of 
rotor 24 along retaining ring 38. Indexer plate assembly 60 is secured to 
indexer 58 by cantilever spring fasteners 72. Fasteners 72 permit proper 
alignment of assembly 60 within indexer 58 regardless of the size of gap 
80 between rotor 24 and stator 32 (See FIG. 2). 
Indexer 58 travels over chains 68 by engaging gears 74 with chains 68. 
Gears 74 are rotated by rod 228, which is rotated by gear engagement 70. 
Gear engagements 70, driven by tangential drive motor 116, ensure proper 
lateral movement of indexer 58 as it rotates about rotor 24. Power to 
motor 116 is delivered through cable 54. Chains 68 fit into grooves on 
track belt 64, which is secured to rotor 24 with straps 66. Track belt 64 
ensures proper alignment of chains 68 such that indexer 58 will not rotate 
unevenly around rotor 24. Proper tension of chains 68 is maintained by 
chain tensioners 136. 
Electrical, video and control signals are transmitted to and from computer 
and video system 22 to indexer 58 and carriage 62 through cables 54 and 
230, respectively (one of each shown). Video data on cables 54 and 230 are 
displayed on monitor 46 and recorded for further inspection on recorder 
42, which is controlled by controller 44. Electrical signals are displayed 
on monitor 48 and may be stored on computer disk drive 51. Microprocessor, 
or computer, 52 permits computational analysis of the incoming electrical 
signals which can also be displayed on monitor 48 or downloaded to printer 
40. Keyboard 50, which includes a full ASCII computer keyboard and an 
operator control panel, permits the operator of system 22 to control 
operation of carriage 62, indexer plate assembly 60, and indexer 58, as 
well as the LI assembly, the WT assembly, and the camera assembly. 
FIGS. 2 and 3 show end views of carriage 62, assembly 60, and indexer 58 
engaged with stator 32. Encoder wheel 76 of carriage 62 provides 
information pertaining to the relative position of carriage 60 to the 
operator and ensure that carriage 62 travels smoothly and evenly within 
stator 32 when wheels 84 and 102 are engaged with carriage slots 34 of 
teeth 28. Connectors 56 and 174 are connected to cables 230 to transmit 
video and electrical signals to and from carriage 62 and computer and 
video system 22. Gear motor 86 drives wheels 84 and 102 to drive carriage 
62 into and out of stator 32. 
Lips 98 of housing top 96 engage slightly with wedge grooves 34 of teeth 28 
which are opposite from those slots 34 which are engaged by wheels 84 and 
102. This ensures proper positioning of indexer plate assembly 60 and, 
thus, proper alignment of carriage 62, by wheels 84 and 102, within wedge 
grooves 34. Proper alignment of carriage 62 by wheels 84 and 102 permits 
even and smooth traversement along slots 34. Wedge 90, which fits into 
slots 36, retains stator coils 30 and prevents them from vibrating. 
Housing top 96 and housing bottom 94 of indexer plate assembly 60 retain 
carriage 62 prior to inspection. Top 96 is connected to bottom 94 with 
adjustable screws 92. This permits indexer plate assembly 60 to adjust to 
the width of a stator slot. 
FIG. 4 shows a front view of carriage 62 engaged with stator 32 and shows 
portions of LI assembly 143. The front end of carriage 62 contains video 
camera 194 and ferrite plugs 142, mounted in blocks 110. Camera 194 allows 
the operator to view the inside of stator 32 through lens 106. Mirror 108 
permits the operator to scan the entire interior of stator 32. Lamp 104 
provides lighting for visual analysis. Coils 112, held by clamp 168, are 
connected to ferrite plugs 142. This arrangement, known as "ELCID", as 
described above, permits laminated plates 26 to be tested for insulation 
breakdowns. Mountings 114 and leverments 78 control the placement of 
blocks 110 against plates 26 during testing. Movement of leverments 78 and 
mountings 114 are described below. 
FIG. 5 shows an exploded view of indexer plate assembly 60 and indexer 58. 
Indexer plate assembly 60 is constructed from base plate 122, housing 
bottom 94, housing top 96 and removable cover 124. lndexer 58 is sized and 
shaped to permit base plate 122 to fit within indexer 58. Fasteners 72 are 
so sized and shaped as to engage with U-shaped slots 138 of indexer 58. 
Mounts 128, which support fasteners 72, rest on plate springs 132. Springs 
132 are then secured to plate 122 by fasteners 126 and 134. This 
arrangement permits proper adjustment of indexer plate assembly 60 within 
indexer 58. 
Carriage 62 is so sized and shaped as to fit into opening 144, which is 
formed when top 96 is connected by fasteners 92 to bottom 94. Bottom 94 
slides forward and backward on base plate 122 to further permit proper 
alignment of assembly 60 within stator 32. Linear bearings 263, which 
slide on shafts 261 secured to base plate 122 by shaft mountings 260, 
ensure smooth movement of bottom 94. Grooves 250 on top 96 engage wheels 
84 and 102 of carriage 62 during pre-inspection preparations. Grooves 250 
ensure proper alignment of carriage 62 within opening 144 and help to 
guide carriage 62 during initial engagement of slots 34 and wheels 84 and 
102. 
Cover 124 conceals most of grooves 250 when it is in place. Cover 124, when 
fastened to top 96 by attachments 152 and 154 (sold under the trademark 
"VELCRO"), adjusts the width of top 96 such that indexer plate assembly 60 
can be used for inspection of variously sized generators. Cover 124 is so 
sized as to adjust the width of top 96 to the space between teeth 28 of 
stator 32. Indentations 146, sectors 148, flanges 150, and cover 124, when 
attached to top 96, slidingly engage with notches 270, 272, 274, and 276, 
respectively, when indexer plate assembly 60 is engaged with stator 32 
during inspection set up. 
As is known in the art, notches 270, 272, 274, and 276 are in an area of 
generator 20 known as the stator step iron region. This region is notched 
to prevent buildup of heat caused by magnetic flux generated internally, 
as is known in the art. Engagement of notches 270, 272, 274, and 276 by 
indentations 146, sectors 148, flanges 150, and properly installed cover 
124, respectively, further ensure proper assembly 60 and, thus, carriage 
62 engagement with stator 32. 
FIG. 6 shows a sectional view of a tooth 28 and the position of coils 30. 
Laminates 26, which make up tooth 28, are tested by LI assembly 143 of 
carriage 62 for insulation deterioration. Coils 30 are stacked in pairs, 
one on top of the other, in the stator slots between teeth 28. Backing 
plate 158, made of non-conducting material, is placed on face 157 of coil 
30 closest to the interior of stator 32. Plate 158 provides a ridged 
surface between face 157 and wave spring 156. Wedge 90 is then used to 
secure coils 30 within stator 32. Edges 154 of wedge 90 are shaped to fit 
wedge grooves 34 so that wedge 90 is snugly fit into wedge grooves 34. The 
springs 156 sometimes lose some of their resiliency during the life of the 
generator, and, thus, the wedges become loose. The WT assembly inspects 
for such a condition. 
FIG. 7 shows a top view of carriage 62 placed within assembly 60. Assembly 
60 is resting in indexer 58, which rides on chains 68. Axial motor 232 
controls the motion of assembly 60 within stator 32. Encoder 234 transmits 
the relative circumferential position of indexer 58 to the operator. 
Infrared switch 280 and limit switch 282 relay back to the operator the 
relative position of indexer plate assembly 60. Infrared switch 280 is 
actuated when indexer plate 60 reaches its EXTEND position, in which it is 
registered with a slot. Limit switch 282 is actuated when indexer plate 60 
assumes its HOME position, in which it is located within indexer 58. Once 
switch 280 detects proper registration and alignment of assembly 60 within 
stator 32, motor 232 is disabled, preventing further movement of assembly 
60 until inspection of the stator slot is complete and the carriage is in 
its HOME position. 
Lid 172 covers the top of carriage 62. Openings 284 allow shafts 176 and 
178, on which wheels 102 and 84, respectively, rotate, to rotate freely 
when adjusters 188 and 190 are used to adjust relative placements of 
shafts 176 and 178. Adjusters 188 and 190 increase or decrease the tension 
on shafts 176 and 178. This causes the alignment of wheels 84 and 102 to 
change such that carriage 62 can travel down any sized slot formed between 
teeth 28. Guide wheels 162, which are spring mounted in mount 160, ensure 
proper engagement of the front end of carriage 62 with wedge grooves 34 of 
teeth 28. 
WT assembly 199 includes microphone, or acoustic sensor, 198 and solenoid 
196, which perform the WT inspection as described above. Ejector 166 of 
solenoid 196 impacts a face 290 of wedge 90. Cup 164 of microphone 198 is 
placed against face 290 and permits microphone 198 to pick up the 
resulting sound of the impact caused by ejector 166. 
FIGS. 8 through 11 show views of carriage 62. Motor 86 drives pinion gear 
180, which is engaged with bevel gear 206. Gear 206 causes shaft 193 to 
rotate chain 191 (on sprockets not shown). Shaft 176, rotated by chain 
191, further rotates chain 182. Chain 182 is looped over sprockets 184 and 
186, which rotate shafts 176 and 178. When shafts 176 and 178 rotate, 
wheels 102 and 84, respectively, also rotate. Motor 86 can turn pinion 
gear 180 clockwise or counterclockwise which permits carriage 62 to move 
in either direction within a stator slot. Adjusters 188 adjust the lateral 
movement of shafts 178, and, consequently, wheels 84. This permits wheels 
84 and 102 to engage slots 36 of teeth 28 regardless of the space between 
teeth 28. Tension on chain 182 is controlled by adjuster 190, which is 
connected to sprocket mount 302. Shaft 176 and sprocket 184 closest to 
camera 194 are mounted in mount 302. As adjuster 190 is turned, mount 302 
will move toward or away from motor 86. Setting adjusters 188 will dictate 
how adjuster 190 should be turned to maintain proper tension on chain 182. 
Infrared switch 402 sends a signal to the computer indicating that carriage 
62 has reached the end of a stator slot. Accordingly, carriage 62 will not 
fall out of a slot 34 if it is driven too far. Infrared switch 404 sends a 
signal to computer 52 indicating that carriage 62 has reached its HOME 
position and is within indexer plate assembly 60. 
Encoder wheel 76 transmits back to the operator the relative position of 
carriage 62 when it is inside stator 32 through encoder 340. This permits 
the operator to know the exact location of any loose wedges 90 or 
deteriorated insulation on plates 26 so proper action can be taken. Mirror 
rotate encoder 406 relates back the position of mirror 108 as it is 
rotated by timing belt 324. This allows the operator to know the exact 
section of generator 20 being visually inspected by camera 194. 
Motors 210, 212, and 214 operate, respectively, WT assembly 199, LI 
assembly 143, and mirror 108 tilt. Motor 210 moves WT assembly 199 between 
an EXTEND position, in which it can impact a wedge, and a RETRACT 
position, in which carriage 62 can be moved. Motor 212 moves LI assembly 
143 between an EXTEND position, in which an LI inspection can be 
performed, and a RETRACT position. Motor 214 tilts mirror 108 about an 
axis that is perpendicular to the latitudinal axis of camera 194 and that 
lies in the plane of FIG. 8. Motor 210, when activated, causes wedge 
tightness frame 226 to lift from its passive RETRACT position within 
carriage 62 to its active EXTEND position, about pivot 360, whereby cup 
164 of microphone 198 is placed near face 290 of wedge 90. 
Computer 52 causes ejector 166 of solenoid to impact against face 290 of 
wedge 90. The resulting noise from the impact is sensed by microphone 198 
and is transmitted back to the computer through cable junction 174 and 
cable 230. The translation of motor 210 rotational movement to linear 
movement of frame 226 is accomplished by a similar arrangement (but not 
shown for clarity reasons) of cables 220, springs 224, and pulleys 222, as 
shown in FIG. 11, which is shown for motor 212. Motor 212, when activated, 
causes LI assembly 143 to be raised. Rotational motion of motor 212 is 
translated, by the cables 220, pulleys 222, and springs 224 systems shown 
in FIG. 11, to linear movement which causes levers 204 to rise and fall. 
Movement of levers 204 controls plates 78 and 114, which, in turn, raise 
and lower support brackets 310. As support brackets 310 are raised and 
lowered, ferrite plugs 142 come into contact with plates 26 of teeth 28 to 
check for insulation deterioration. Motor 214, when activated, causes 
mirror 108 to tilt, enabling the operator to view airgap 80 of stator 32. 
A cable 220 and pulleys 222 system (not shown for clarity) causes pulley 
324 to take up or let out cable 208, which is connected to mirror assembly 
170, causing mirror 108 to tilt up or down. Spring 167 ensures that mirror 
108 returns to its proper tilt position after airgap 80 is inspected. 
Motor 326 controls the rotation of mirror assembly 170 about the 
longitudinal axis of camera 194 Motor 326 causes shafts 328 and 330 to 
rotate, causing chain 202 to rotate around sprocket 324 of mirror assembly 
170. An encoder 406 provides information pertaining to the relative 
rotational position of mirror 108. Motor 342 controls the focus mechanism 
of camera 194. As shaft 344 is rotated by motor 342, gear 346 engages and 
rotates gear 218. Shaft 300, resting on supports 348 and 330, rotates as 
gear 218 rotates, causing timing belt 200 to move the lens in camera 194. 
FIGS. 12 through 21 show schematically the details of the electrical 
control system for the generator inspection assembly. FIG. 12 shows a 
block diagram of system 400. System 400 includes a microprocessor, or 
computer, 52, which can be accessed through an ASCII keyboard located on 
operator keyboard 50. Microprocessor 52 coordinates the operation of 
system 400 and controls the acquisition, storage and dissemination of 
information developed by system 400. 
A conventional bus expansion chassis 408 is provided to permit 
microprocessor 52 to communicate with the control modules of system 400. 
Camera 194 is a conventional, commercially available camera which supplies 
a composite video signal to microprocessor 52 via its camera power supply 
410. Depending on the mode of operation, microprocessor 52 either can pass 
the composite video signal directly to VCR 42, which is preferably of VHS 
formate for real-time display or it can digitize one or more frames of 
video and save them for later display through VCR 42. VCR 42 displays 
video supplied to it from microprocessor 52 on color monitor 48. 
Conventional VCR remote controller 412 permits remote operation of VCR 42. 
Keyboard 50, which is part of operator control panel 414, includes the 
switches and indicator lights necessary to permit the system operator to 
perform a generator inspection. Generally, operator control panel 414 
includes: 
(1) Switches that permit the operator to rotate and tilt mirror 108; 
(2) A control that permits adjusting the intensity of the carriage lighting 
system; 
(3) A pair of switches that permits the operator to jog the carriage or 
indexer; 
(4) A switch that permits the operator to adjust the focus of the camera; 
(5) Indicator lights that are energized when the limits of camera focus, 
mirror rotation and mirror tilt have been reached; 
(6) Indicator lights that are energized when mirror encoder 403 is 
producing pulses; 
(7) Switches that permit the operator to stop the carriage or the indexer 
in a controlled or uncontrolled fashion; 
(8) An indicator light that is energized when the carriage or indexer 
emergency stop switch has been actuated and the indexer or carriage is 
being brought to an uncontrolled stop; 
(9) An indicator lamp that is energized when power is available from the 
system console; 
(10) An indicator lamp that is energized when that the console is receiving 
power from a suitable source; 
(11) An operator screen that provides and requests information pertaining 
to system operation. 
System 400 also includes four control modules. Carriage control module 416 
controls the operation of carriage main drive motor 86, camera focus motor 
342, mirror tilt motor 214, and mirror rotate motor 326. Carriage control 
module 416 receives information from front and back carriage sensors 402 
and 404, carriage main drive motor position encoder 340, and mirror rotate 
motor encoder 406. Front sensor 402 is actuated when carriage 62 reaches 
its limit of travel at the end of a stator slot. Back sensor 404 is 
actuated when carriage 62 reaches its HOME position. 
Indexer control module 418 controls the operation of indexer main drive 
motor 116 and indexer plate motor 232. Indexer control module 418 receives 
information from indexer main drive motor position encoder 234 and indexer 
plate EXTEND and HOME sensors 280 and 282. EXTEND sensor 280 is actuated 
when indexer plate 60 is in registration with a stator slot. HOME sensor 
282 is actuated when plate 60 is in its HOME position within indexer 58. 
Sensor interface module 420 controls the operation of wedge tightness 
drive motor 210, lamination inspection drive motor 212, and LI coils 112. 
Module 420 also receives information pertaining to lamination integrity 
from coils 112. Power supply module 422 provides a 28 volt supply for 
motors 86, 116, 232, 210, and 212, plus a 5 volt supply for the logic 
circuitry of modules 416, 418, and 420, plus and minus 15 volt supply for 
the analog circuitry of modules 416, 418, and 420, and plus 7.5 volt 
supply for focus motor 342, mirror tilt motor 214, and mirror rotate motor 
326. 
Carriage control module 416 controls operation of carriage main drive motor 
86. Carriage control module 416 employs a pulse width modulator to drive 
carriage motor 86. Module 416 further includes fault detection logic that 
detects motor 86 lead faults. Module 416 also includes current limiting 
circuitry that limits the maximum current flowing eight status indicator 
lamps that indicate: 
(1) the direction of rotation of motor 86; 
(2) that motor 86 is not rotating; 
(3) the existence of a problem executing the current command; 
(4) that front carriage sensor 402 has indicated that the front limit for 
the carriage has been violated; 
(5) that back carriage sensor 404 is indicating that carriage 62 has 
reached its HOME position 
(6) that encoder 340 channel A is sending pulses to module 416; 
(7) that encoder 340 channel B is sending pulses to module 416; 
(8) the existence of a fault on a lead of motor 86. 
Module 416 communicates with a reset switch, which is located on the module 
front panel of module 416 that permits the operator to reset module 416 
and restart motor 86 after a fault has occurred. 
Module 416 also controls the tilt and rotation of camera mirror 108 and the 
focus of camera 194. Module 416 communicates with a current meter located 
on panel 414 that displays the current flowing through any one of motors 
342, 214, and 326 chosen by the operator. Module 416 also determines when 
mirror 108 has been rotated to one of its mechanical limits and, at that 
point, shuts down the voltage and current to mirror rotate motor 326. 
Module 416 detects faults on the leads of motors 342, 214, and 326 and 
provides current limiting for those motors. Module 416 also communicates 
with a reset switch which permit motors 342, 214, or 326 to be restarted 
after a fault has occurred. 
FIG. 13 shows in schematic form carriage control module 416. Module 416 
includes the primary control circuit board 424. Board 424 controls the 
energization of the eight status indicator lamps 426 through 433 
identified above. Board 424 also includes rack compatible connector 434 
that permits board 424 to be plugged into the rack of computer 52 and to 
provide electrical communication therebetween. Module 416 communicates 
with a current meter 436, which senses the current flowing through motor 
86, and a volt meter 438 which senses the voltage across motor 86. Both 
meters 436 and 438 are located on the front panel of module 416. 
Carriage main drive motor position encoder 340 provides position signals to 
board 424 via differential line driver 440. Differential line driver 440 
produces a pair of position signals on lines 442 and 444. Line 442 carries 
the channel A signal produced by encoder 340 and the inverted channel A 
signal. Line 444 carries the channel B signal produced by encoder 340 and 
the inverted channel B signal. The channel A and channel B signals 
produced by encoder 340 are electrically separated by 90 degrees. Board 
424 includes encoder logic that receives and processes the information it 
receives from driver 440. Board 424 energizes indicator lights located on 
panel 414 when sensors 402 or 404 indicate that a carriage travel limit 
has been reached. Board 424 generates a signal that disables motor 86 and 
energizes an indicator lam on panel 414 when a limit has been reached. 
Module 416 also includes mirror rotate control board 446. Board 446 
controls the operation of mirror rotate motor 326. Board 446 communicates 
with a current meter 448, which is located on operator control panel 414 
and displays motor 326 current. Board 446 includes rack compatible 
connector 450 to permit board 446 to be plugged into the rack of computer 
52 and 0 provide electrical communication therebetween. Encoder 406 
communicates with board 446 through differential line driver 452, which is 
identical to differential line driver 440 described above. 
Module 416 also includes camera focus motor 5 control board 454 and mirror 
tilt motor control board 456. Board 454 controls the operation of camera 
focus motor 342, and board 456 controls operation of mirror tilt motor 
214. Board 454 includes connector 458 which plugs into a mating connector 
located on board 446. Board 456 includes connector 460 which plugs into a 
mating connector located on board 446. Connectors 458 and 460 permit 
electrical communication between board 446 and each of boards 454 and 456. 
Each of boards 446, 454, and 456 includes a motor amplifier, fault 
detection logic, and reset circuit. Each of boards 454 and 456 is 
identical to board 446, with the exception that they have no logic to 
interface with a position encoder or differential driver. Mirror rotate 
control board 446 includes logic that receives signals from driver 452 
when encoder 406 is producing pulses. Board 446 provides a signal that 
energizes an indicator lamp on control panel 414 when a clockwise or 
counterclockwise limit of mirror rotation has been reached. Board 446 also 
disables the mirror rotate motor 326 when a rotation limit has been 
reached to prevent the limit from being exceeded. Board 446 also energizes 
an indicator light on panel 414 when it disables motor 326. Current meter 
448 provides an indication of the motor supply current for the motor 326, 
342, or 214, that is currently operating Boards 424, 446, 454, and 456 
further provide appropriate amplification to operate motors 86, 326, 342, 
and 214. 
Indexer control module 418 controls the operation of indexer main drive 
motor 116 and indexer plate motor 232. Module 418 includes primary motor 
control board 462 and indexer plate control board 464. Primary motor 
control board 462 controls the operation of indexer main drive motor 116. 
Board 462 provides signals to energize indicator lamps 466 and 468 located 
the front panel of module 418. Indicator lamp 466 is energized when 
channel A of encoder 234 is producing pulses and indicator lamp 468 is 
energized when channel B of encoder 234 is producing pulses. 
Board 462 includes a rack compatible connector 470 that can be plugged into 
the rack on computer 52 to provide electrical communication therebetween. 
Board 462 communicates with current meter 472, which is located on the 
front panel of module 418 and indicates the level of motor current 
supplied to motor 116. Board 462 also communicates with volt meter 474, 
which is located on the front panel of module 418 and indicates the level 
of voltage across the leads of motor 116. Encoder 234 electrically 
communicates with differential line driver 476, which is identical to 
differential line driver 440. Board 462 communicates with a reset switch 
located on the front panel of module 418 that permits restarting of motor 
116 after occurrence of a motor fault. Control board 462 is identical to 
board 424. 
Indexer plate control board 464 electrically communicates with indicator 
lamps 478 and 480. Indicator lamp 478 is energized when the indexer plate 
is being moved at its fast speed. Indicator lamp 480 is energized when the 
indexer plate is being moved at its slow speed. Board 464 communicates 
with a reset switch located on the front panel of module 418 that permits 
the operator to restart motor 232 after a fault condition has occurred. 
Board 464 includes a rack compatible connector 484 that can e plugged into 
computer 52 to provide electrical communication therebetween. A current 
meter 486 is located on control panel 414 and indicates the level of the 
current flowing into motor 232. Board 464 communicates with mechanical 
limit switch 282, which closes when indexer plate 60 has reached its HOME 
position. Board 464 also communicates with sensor 280, which closes when 
indexer plate 60 has reached its EXTENDED position. Motor 232 is disabled 
when either of sensors 282 or 280 is activated. Board 464 includes an open 
loop pulse width modulator control circuit to control operation of motor 
232. 
Sensor control module 420 controls operation of lamination integrity lift 
motor 212, wedge tightness lift motor 210, impact solenoid 196, and 
acoustic sensor 198. Sensor control module 420 includes a sensor interface 
board 488. 
Board 488 communicates with eight indicator lamps 490 through 497. 
Indicator lamp 490 is energized when WT assembly 199 is in its RETRACT 
position. Indicator lamp 491 is energized when computer 52 releases wedge 
tightness impactor 166. Indicator lamp 493 is energized when a wedge 
tightness inspection is being executed, that is, when wedge tightness 
impactor 166 is commanded to impact a wedge several times and acoustic 
data from the impacts is being gathered. 
Indicator lamp 493 is energized when LI assembly 143 is in its retracted 
position. Indicator lamp 494 is energized when LI coils 112 produce an 
electrical signal that exceeds upper or lower limits. Indicator lamp 495 
is energized when computer 52 is executing an LI inspection. Indicator 496 
is energized 0 when a fault condition exits on motor 212. Indicator 497 is 
energized when a fault condition exists on motor 210. 
As shown in FIG. 15, board 488 communicates with WT solenoid 196 and WT 
acoustic sensor 198. Board 5 488 receives commands from computer 52 and 
produces signals to activate solenoid 196. Board 488 also includes an 
acoustic signal conditioning circuit that receives acoustic signals from 
sensor 198. Board 488 also communicates with a current meter 498, which 
indicates the level of current being supplied to the lamination integrity 
lift motor 210 or wedge tightness lift motor 212 that is energized. 
Board 488 also includes rack compatible connector 500 which can be plugged 
into the rack of computer 52 to provide electrical communication 
therebetween. Module 420 also includes motor control boards 502 and 504. 
Motor control board 502 controls the operation of lamination integrity 
lift motor 212. Motor control board 504 controls the operation of wedge 
tightness lift motor 210. 
Board 502 includes connector 506 that can be plugged into a mating 
connector located on board 488 to provide electrical communication 
therebetween. Board 504 includes connector 508 that can be plugged into a 
mating connector located on board 488 to provide electrical communication 
there between. Only one of motors 210 and 212 can be operated at any one 
time, and current meter 498 indicates the level of current supplied to the 
motor 210 or 212 that is operating. Boards 502 and 504 are identical to 
boards 454 and 456. 
Board 488 controls the operation of impact solenoid 196 and conditions and 
amplifies the signal produced by acoustic sensor 198. Board 488 filters 
noise from the signal produced by sensor 198 and provides an indication, 
via lamp 494, when upper or lower limits for sensor 198 signal have been 
exceeded. 
Sensor 198 produces a distorted sine wave. Board 488 determines the times 
between peaks in the distorted signal produced by sensor 198. As is known 
in the art, the tighter the stator coil wedge, the smaller the difference 
in time between peaks in the signal produced by sensor 198. Board 488 also 
communicates with a reset switch, located on the front panel of module 
420, that can be used by the operator to restart a motor 210 or 212 after 
a fault condition has occurred. 
Computer 52 controls the wedge tightness inspection process. Computer 52 
initiates the wedge tightness inspection process by activating impact 
solenoid 196 and starting a timing circuit. Impact solenoid 196 causes 
impactor 166 to hit a wedge and the resulting acoustic information is 
collected by acoustic sensor 198. Acoustic sensor 198 produces an 
electrical signal corresponding to the acoustic data it receives and 
provides the electrical signal to board 488 for conditioning. If board 488 
receives an acoustic signal from sensor 198, a normal procedure has 
occurred, and the timing circuit is reset. However, if either impactor 166 
did not hit a wedge or if sensor 198 does not produce an acoustic signal 
that turns off the command that released impactor 166, the timing circuit 
times out and computer 52 recognizes an abnormal or error condition. 
Power supply module 422 is shown in FIG. 14 
Module 422 includes multi-output power supply 410, which provides the +28, 
+5, +15, -15, and +7.5 volt identified above Board 410 communicates with 
fuses 412 through 416, located on panel 414, which correspond to each 
voltage level supplied by board 410. Board 510 also includes rack 
compatible connector 518, which can be plugged into the rack located on 
computer 52 to provide electrical communication therebetween. Module 422 
also includes blown fuse indicator board 520. Board 520 communicates with 
five indicator lamps, 522 through 526, located on panel 414. Each of lamps 
522 through 526 corresponds to a fuse 512 through 516 and is energized 
when that fuse blows. 
FIG. 16 shows differential line driver 440, encoder 340, and differential 
line receiver 528. Each of boards 424, 446, and 462 includes differential 
line receivers that are identical to hose shown in FIG. 16. As was 
described generally above, encoder 340 produces two square waves A first 
square wave, produced by channel A, is generated on line 530 A square wave 
that is 90 electrical degrees out of phase with channel A is produced by 
channel B of encoder 340 on line 532. 
Differential line driver 440 produces the channel A signal on line 534, the 
inverted channel A signal on line 536, the channel B signal on line 538, 
and the inverted channel B signal on line 540. Differential line receiver 
528 produces the channel A signal on line 542 and the channel B signal on 
line 544. Differential line driver 440 and differential line receiver 528 
eliminate common mode noise occurring between channels A and B, which is 
injected during transmission of the channel A and channel B signals during 
transmission from encoder 340 to board 424. 
Differential line driver 440 and differential line receiver 528 also 
produce signals on lines 542 and 544 which permit computer 52 to determine 
the direction of rotation of motor 86. The operation and construction of 
encoder 340, differential line driver 440, and differential line receiver 
528 are all conventional and well known to those of ordinary skill in the 
art. 
FIGS. 17 and 18 show in block diagram form the circuit contained on primary 
motor control board 424. Circuits that perform the functions of the blocks 
shown in FIGS. 17 and 18 are well known and commercially available. 
FIG. 17 shows indicator lamps 426 and 427. Lamp 426 flashes when encoder 
340 is producing pulses on channel A. Lamp 427 flashes when encoder 340 is 
producing pulses on channel B. Differential line receiver 528 receives the 
channel A signal on line 534, the inverted channel A signal on line 536, 
the channel B signal on line 538, and the inverted channel B signal on 
line 540. 
As described above, differential line receiver 528 produces the channel A 
signal on lines 542 and 546 and the channel B signal on lines 544 and 548 
A pair of divide-by-32 circuits 550 and 552 receive the channel A and 
channel B signals, respectively, and reduce the frequency of the channel A 
and B signals to a level at which they cause lamps 426 and 427 to flash at 
a visually perceptible rate. 
Lamp driver 554 receives the signals produced by the circuits 550 and 552 
on lines 556 and 558, respectively, and boosts those signals to a level 
sufficient to energize lamps 426 and 427. The output of driver 554 is 
provided to lamps 426 and 427 along lines 560 and 562, respectively. 
Computer 52 receives the channel A and channel B signals along lines 546 
and 548, respectively. Computer 52 uses those signals to determine the 
position of carriage 62. 
Module 424 receives signals from carriage sensors 402 and 404 along lines 
564 and 566, respectively. Amplifiers 568 and 570 have adjustable 
sensitivities to compensate for varying distances between sensors 402 and 
404, and the interior of stator 32 to ensure that amplifiers 568 and 570 
produce signals of a consistent level. Indicator lamp 428 is energized 
when the carriage travels too far through stator 32 and attempts to exit 
stator 32, thus exceeding a limit of travel. 
Indicator lamp 429 is energized when carriage 62 reaches its HOME position. 
When carriage 62 has traveled too far through stator 32 and is about to 
exit stator 32, sensor 404 produces a signal on line 564 that is amplified 
by amplifier 568. The amplified signal is produced on line 572 and 
provided to lamp driver 574. Similarly, sensor 402 produces a signal on 
line 566 when carriage 62 reaches its HOME position, which signal is 
amplified by amplifier 570 and provided to driver 574 on line 576. Lamp 
driver 574 boosts the signals on lines 572 and 576 to a level that is 
sufficient to drive indicator lamps 428 and 429 
The outputs of amplifiers 568 and 570 are also produced on lines 578 and 
580, respectively The signals on lines 578 and 580 are provided to 
computer 52 to permit it to determine when carriage 62 has reached either 
limit of its travel. 
FIG. 18 shows the portion of board 424 that controls the operation of motor 
86, limits the current into motor 86 and detects faults on motor 86. 
Pulse-width modulator control logic 582 drives motor 86 through FET 
H-bridge 584. Driving current is supplied to motor 86 along lines 586 and 
588. Both pulse width modulator control logic 582 and H-bridge 584 are 
well known to those of ordinary skill in the art. 
H-bridge 584 allows bi-directional motor rotation and control using a 
single-ended power supply. Direction control logic 590 receives a 
direction signal from computer 52 along line 592. Direction control 590 
produces direction signals on lines 594 and 596 that determine the 
direction in which motor 86 rotates. 
Indicator lamp 430 receives a direction signal from line 592 and indicates 
the direction in which motor 86 is rotating. The direction signal is also 
provided to pulse width modulator control logic 582 along line 598. Pulse 
width modulator control logic 582 receives pulse width modulated signals 
from computer 52 along line 600. Pulse width modulator control logic 582 
provides control for pulse width modulated signals for each half of 
H-bridge 584 along lines 602 and 604. 
Emergency stop relay 606 receives 28 volts DC from power supply module 422 
along line 608. Relay 606 receives a signal along line 610 when the 
emergency stop switch on operator control panel 414 has been actuated by 
the operator. The emergency stop actuator switch is thrown by the operator 
when the operator wishes to immediately stop carriage travel. When relay 
606 receives the emergency stop signal on line 610, relay 606 turns off 
current flowing in signal 612 which, in turn, causes H-bridge 584 to shut 
down motor 86. When an emergency stop signal is not present on line 610, 
current limiter 614 permits the H-bridge 584 to operate motor 86 normally, 
unless the maximum current level is exceeded. 
Computer 52 produces a signal on line 618 that commands board 424 to 
disable motor 86 when carriage 62 reaches a limit of its travel. When a 
carriage disable signal is produced on line 618, axis disable circuit 620 
produces signals on lines 622, 624, and 626 that cause direction control 
circuit 590, pulse width modulator control logic circuit 582, and H-bridge 
584 to disable motor 86. A signal on line 622 is provided to computer 52 
to inform computer 52 that motor 86 is inoperable. When computer 52 
produces a command on line 618 to disable motor 86, indicator light 431 is 
energized. 
A manual disable switch 628 is provided on board 424 to permit the operator 
to manually disable carriage motor 86. When the operator closes switch 
628, the signal on line 630 causes axis disable circuit 620 to produce a 
signal on line 622 that causes direction control circuit 590, pulse width 
modulator control logic 582, and H-bridge 584 to disable motor 86 and to 
inform computer 52 that motor 86 has been disabled. Closing switch 628 
also causes indicator 432 to be energized, indicating that a manual 
disable has been effected. 
Resistors 632 and 634 are connected in lines 586 and 588, respectively, to 
permit fault detection monitoring of motor 86 leads. Fault detection 
circuit 636 receives the voltage across resistors 632 and 634 via leads 
638, 640, 642, and 644. Circuit 636 thus can determine whether the current 
entering motor 86 is at the same level as the current leaving motor 86 by 
detecting the voltage across resistors 632 and 634. 
If the currents entering and exiting motor 86 are not equal to each other, 
circuit 636 assumes that a fault condition exists, and it instructs axis 
disable circuit 620 to shut down motor 86 by generating an appropriate 
signal along line 646. The fault indication signal on line 646 is also 
provided to computer 52 along line 648 to inform computer 52 that a fault 
condition exists and also energizes fault indicator lamp 433, which is 
located on board 424. Fault detection circuit 636 latches the fault signal 
on line 646 to prevent motor 86 from being restarted until reset switch 
650 is actuated by the operator When reset switch 650 is actuated, circuit 
636 removes the fault signal from line 646, indicator lamp 433 is 
de-energized, and motor 86 can be restarted. 
FIG. 19 shows indexer plate control board 464. Control board 464 includes 
pulse width modulator control logic circuit 658 and FET H-bridge 656. 
H-bridge 656 drives motor 232 either in a direction that causes indexer 
plate 60 to move toward stator 32 or away from stator 32. Direction 
control logic 660 receives direction signals on lines 662 and 664. The 
signal on line 662 commands direction control circuit 660 to turn motor 
232 in a direction that moves indexer plate 60 away from stator 32. The 
signal on line 664 commands direction control logic 660 to rotate motor 
232 in a direction that moves indexer plate 60 towards stator 32. 
Emergency stop relay 652 and current limiter 654 are identical to relay 606 
and limiter 614 shown in FIG. 18, with the exception that limiter 614 
limits motor 86 to 3.0 amps and limiter 654 limits motor 232 to 1.5 amps. 
Optical isolator 666 receives a signal on line 668 from sensor 282 that 
indicates that indexer plate 60 has been fully retracted and is in the 
HOME position. When such a signal is received on line 668, direction 
control 660 is commanded o stop rotation of motor 232 to halt indexer 
plate 60 travel by a signal on line 670. Optical isolator 666 provides an 
interface and isolation between sensor 282 and direction control 660. 
When a HOME signal is received on line 668, optical isolator 666 produces a 
signal on line 672 that informs computer 52 that indexer plate 60 has 
reached its HOME position. When indexer plate 60 has reached its EXTEND 
position, in which carriage 32 is in a position to enter a stator 32 slot, 
sensor 280 produces an EXTEND signal on line 674. 
Amplifier 675 includes sensitivity adjustment 676 to compensate for varying 
distances between sensor 280 and stator 32 to insure that a consistent 
signal input is produced to direction control circuit 660 and computer 52. 
Amplifier 676 produces a signal on line 678, when an EXTEND signal is 
produced on line 674, that instructs direction control circuit 660 to stop 
operation of motor 232 and informs computer 52 that indexer plate 60 has 
reached its EXTEND position and that motor 232 is not operating. 
Resistors 680 and 682 are inserted in lines 684 and 686, which communicate 
electrically with the leads of motor 232. Fault detection circuit 688 
receives the voltage across resistors 680 and 682 via lines 690, 692, 694, 
and 696. Fault detection circuit 688 is identical to fault detection 
circuit 636 shown in FIG. 18, and when the voltage across resistors 680 
and 682 are not equal to each other, produces a FAULT signal on line 698 
that causes pulse width modulator circuit 658 to shut down motor 232. The 
fault signal on line 698 is latched until the operator actuates reset 
switch 700 located on the front panel of module 418. 
Before a fast or slow speed for motor 232 can be selected, computer 52 must 
first enable circuits 658 and 660 by activating indexer plate enable 
signal on line 659. 
Pulse width modulator circuit 710 operates motor 232 in its FAST mode 
unless a SLOW signal is received on line 702 from computer 52. The SLOW 
signal on line 702 is received by slow select relay 706 on line 704. The 
SLOW signal on line 704 causes resistor 708 to be injected in the circuit, 
and pulse width modulator circuit 710 reduces the duty cycle of its output 
on line 712. The reduced duty cycle of the signal on line 712 causes 
circuit 658 to operate motor 232 in its SLOW mode. Potentiometer 714 is 
provided to further adjust the duty cycle of the signal on line 712 to 
adjust the speed of rotation of motor 232 in its FAST mode. The SLOW 
signal from computer 52 on line 702 causes lamp driver 716 to energize 
SLOW indicator lamp 478. Absence of the SLOW signal on line 702 causes 
driver 716 to energize FAST indicator lamp 480. 
FIG. 21 shows the acoustic sensor signal conditioner circuit. Acoustic 
sensor 198 produces a distorted sine wave of a frequency that depends on 
the tightness of the wedge undergoing inspection. The distorted sine wave 
is applied to analog buffer 722 along line 720. Buffer 722 permits 
reception of the distorted signal without loading down the signal. The 
buffered acoustic signal is applied to differentiator 728 along line 724 
and window detector circuit 736 along line 726. Differentiator 728 
differentiates the acoustic signal appearing on line 724. The 
differentiated acoustic signal is applied to zero-cross detector 732 along 
line 730. 
Zero-cross detector 732 produces a pulse on line 734 each time the 
differentiated acoustic signal on line 730 crosses zero. Accordingly, the 
time occurring between the rising edges of pulses on line 734 represents 
the time occurring between zero slope points along the signal carried by 
line 720. The closer together the rising edges of the pulses on line 734, 
the tighter the wedge undergoing inspection. The rising edge of each pulse 
on line 734 indicates the zero crossing of the signal on line 730. 
Computer 52 measures the time period between each pulse on line 734. 
Circuits 736 and 740 provide information to computer 52 pertaining to the 
timing of the wedge tightness inspection process. When computer 52 
releases impactor 166, and impactor 166 hits a wedge, sensor 198 produces 
an acoustic signal that is received by window detector circuit 736 along 
line 726. When the acoustic signal on line 726 exceeds a predetermined 
threshold, circuit 736 produces along line 738 a signal that causes 
digital latch 740 to produce a trigger signal on line 742. 
The trigger signal on line 742 is transmitted to computer 52, which 
interprets the presence of a trigger signal as indicating that acoustic 
data is forthcoming. Computer 52 then samples 8 pulses on line 734, at 
which time computer 52 removes from solenoid 196 the signal that caused 
impactor 166 to impact the wedge. At that point, computer 52 resets the 
trigger signal and resets the timing circuit described above. 
Board 446 energizes indicator lamps on operator control panel 414 that 
indicate: 
(1) operation of encoder 406 channel A; 
(2) operation of encoder 406 channel B; 
(3) mirror rotation to clockwise limit; 
(4) mirror rotation to counterclockwise limit. 
Camera focus board 454 and mirror tilt board 456 are identical to mirror 
rotate control board 446 with the exception that they do not include the 
encoder logic shown in FIG. 16. 
Primary motor control board 462 of indexer control module 418 is identical 
to primary control board 424 of carriage control module 416 shown in FIGS. 
17 and 18. 
Lamination integrity lift motor board 502 and wedge tightness lift motor 
control board 504 are 5 identical to motor controllers 454 and 456 shown 
in FIG. 13. 
Operation of the apparatus and electronic system described above can be 
implemented by any suitable computer software. A functional description of 
computer software particularly useful with the preferred embodiment is 
provided below, from which suitable computer programs easily can be 
generated. The system can be operated generally in four active modes, 
lamination integrity, wedge tightness, visual, and manual. 
The program includes a top level mode, main, from which the operator can 
choose one of the four active modes. The system includes one additional 
mode, initialization mode, in which the operator aligns indexer 58 with a 
slot and identifies the slot number for computer 52. Computer 52 reads the 
position from indexer main drive motor position transducer 234 and 
considers that reading to be the HOME, or reference, position. 
When operating the system, the operator enters the main mode and identifies 
the following: 
(1) customer site name; 
(2) operator name; 
(3) plant code; 
(4) generator number; 
(5) site code; 
(6) any additional desired comments. 
Once that data has been entered, computer 52 displays on computer CRT 48 
four active modes and the initialization mode. The system is designed to 
prevent the operator from selecting any of the four active modes until the 
operator had entered generator information and indexer HOME position 
information. Upon returning to main from the initialization mode, the 
operator is given the choice of entering one of the four active modes. 
Upon entering the lamination integrity mode, the operator is given the 
option of entering three submodes, scan process, graph-stored data, and 
return to main. Return to main permits the operator to return to the top 
level mode, main. The scan process mode permits the operator to initiate a 
lamination integrity inspection. Upon entering the scan process submode, 
the operator provides the following to computer 52 via an initialization 
screen: 
(1) number of the slot to be inspected; 
(2) length of slot to be scanned, in inches; 
(3) speed, in inches per second, at which the lamination integrity 
apparatus will travel during the inspection; 
(4) sampling rate, in inches; 
(5) name of the computer file that will store the information developed 
during the scan; 
(6) current range setting; 
(7) whether the carriage should return to its HOME position upon completion 
of the scan; 
(8) speed, in inches per second, at which the carriage should return to the 
HOME position; 
(9) pan increment, in inches; 
(10) cursor increment. 
Upon completion of the initialization process described above, the operator 
initiates the scan. Indexer 58, indexer plate 60, and carriage 62 have 
been previously moved to the inspection site using the manual mode 
described below. Upon initiation of the scan, computer 52 moves carriage 
62 through the specified distance during which lamination integrity 
information is acquired and, if desired, stored. 
Also, during the scan, computer 52 displays graphs of acquired data. 
Computer 52 produces the graphs on screen 48. Upon initiation of the scan 
process, lamination insulation integrity inspection ("LIII") assembly 143 
is raised and ferrite plugs 142 contact stator 32. Then, carriage 62 
begins to move and data is collected. As data is collected, it is 
displayed on screen 48. Voltage generated by lamination integrity coils 
112 is displayed versus slot position. 
Three graphs are provided, representing data acquired from three slots. The 
data from two slots previously scanned and the slot currently under 
inspection are graphed. The display also provides position and current 
fields that are continuously updated as coils 112 move along the slot, 
slot number, the zoom factor, and an indication of which of the three 
graphs represents information currently being obtained from a slot. 
Upon completion of the scan, carriage 62 either returns to its HOME 
position, if the operator so chose during initialization, or carriage 62 
simply stops to await further instructions. If the operator chose to store 
the acquired data, computer 52 creates a file name and stores the data in 
a file under that name along with the slot number and the time of day at 
which the data was collected. 
The graph stored data submode permits the operator to display on screen 48 
a graph of data acquired earlier. Upon entering this submode, the operator 
can display a directory of files previously created. The operator may 
enter the name of up to three files whose data should be graphed. The 
operator also enters the zoom factor, the pan increment in inches, and the 
cursor increment in data points, although default values are provided. The 
graphs are then displayed. The operator then has the option to enter the 
graphics mode, in which the operator can manipulate the graph displayed on 
the operator screen by panning and zooming. 
The graphics mode is a conventional program that can be readily constructed 
by one of ordinary skill in the art. The graphics mode performs 
essentially four functions. Using the graphics mode, the operator can zoom 
in on data displayed on the screen. That is, a portion of the graph can be 
chosen and amplified to encompass the entire available graph on the 
screen. 
After amplification has occurred, the operator can pan the graph to the 
left or right to display amplified data that was outside the portion 
originally chosen with the zoom feature. Also, the cursor, or cross hair, 
can be moved to the left or right to display the current reading and 
position. Finally, the screen, as displayed, can be printed. A more 
detailed description of the scan process submode of the lamination 
integrity mode is provided below, in numbers step form: 
(1) Initialize analog to digital ("A/D") convertor--the A/D receives analog 
data from lamination integrity coils 112 and converts the data to digital 
signals. 
(2) Has the process scan been completed? The scan is complete when carriage 
62 stops or reaches HOME at the end of a scan, or when the operator has 
chosen to exit the lamination integrity mode. If the scan process has 
ended, the scan is complete and the system displays, on screen 48, the 
modes for choice by the operator. 
(3) If the answer in Step (2) is "yes", the scan process submode ends and 
the operator is given the choice of which submode under lamination 
integrity mode to enter. 
(4) If the answer in Step (2) is "no", the lamination integrity 
initialization screen is displayed. 
(5) Initialize operator's screen to display a real-time plot--the 
operator's screen is prepared to display the graphs and data pertaining to 
a lamination integrity scan 
(6) Determine whether carriage 62 may be moved by checking the carriage 
front and back overtravel sensors 402 and 404. 
(7) Ascertain and eliminate the effects of background noise from the A/D 
convertor. 
(8) Command the lamination integrity lift motor 212 to lift lamination 
integrity assembly 143. 
(9) Read the lamination integrity channel of the A/D convertor. 
(10) Check carriage main drive motor 86 for error conditions. 
(11) Energize lamination integrity cycle LED on operator control panel 414 
to indicate a scan is in progress. 
(12) Is the scan still in progress? If not, proceed to Step (23) below. If 
so, proceed to Step (13) below. 
(13) Display on screen 48 present carriage 62 position and slot number. 
(14) Check the computer keyboard for operator input to determine whether 
the operator has ordered carriage 62 to a controlled stop or to an 
immediate stop. 
If the operator has ordered a controlled stop, carriage 62 is decelerated 
to a stop and awaits further instructions. The operator can either return 
to the HOME position or continue the scan. If the operator has ordered an 
immediate stop, carriage 62 immediately stops and the operator may return 
carriage 62 to the HOME position. 
(15) Read main drive motor encoder 340 to determine current carriage 62 
position from HOME, in inches. 
(16) Determine whether the forward scan is complete using the position 
information obtained in Step (15). 
(17) Check carriage main drive motor 86 to determine the presence of any 
errors. 
(18) Check carriage front and back sensors 402 and 404 to determine whether 
carriage 62 may be moved. If carriage 62 may not be moved forward, 
carriage 62 will stop and may be returned to the HOME position. 
(19) Has carriage 62 travelled the specified distance since the last 
measurement? If not, proceed to Step (12) above. If so, proceed to Step 
(20) below. 
(20) Read the voltage from lamination integrity coils 112 via the A/D 
convertor. 
(21) Display the current position and the present current flowing through 
lamination integrity coils 112, calculated from the voltage read in Step 
(20), in graph form on screen 48. 
(22) Store the position and voltage data in resident memory and proceed to 
Step (12) above. 
(23) Since the scan has been completed, de-energize the lamination 
integrity cycle ON LED energized in Step (11) above. 
(24) LIII assembly 143. 
(25) During lamination integrity initialization, did the operator specify 
that the carriage should return to HOME after the forward scan? If not, 
proceed to Step (30) below. If so, proceed to Step (26) below. 
(26) Determine whether the operator wishes to scan while carriage 62 
returns to the HOME position. If the operator answers in the negative, 
proceed to Step (28) below. If the operator answers in the affirmative, 
proceed to Step (27) below. 
(27) Return carriage 62 to the HOME position while scanning. During this 
procedure, return scan data is laid over the forward scan data on screen 
48. 
(28) Return carriage 62 to the HOME position without scanning. 
(29) Store the data acquired on disk. 
(30) Enter graphics mode and remain there until operator exits. 
(31) Disable carriage main drive motor 86. 
The details of the graph stored data submode of the lamination integrity 
mode are described, in numbered step form, below: 
(1) Display graph initialization screen. The screen allows the operator to 
enter three file names corresponding to data that the operator wishes to 
display in graph form. 
(2) Display lamination integrity graph template. The computer displays a 
screen that is blank with the exception of three sets of graph axes. 
(3) Retrieve desired data from disk. The computer retrieves position and 
voltage data from the three files selected. 
(4) Calculate and display graph scale. 
(5) Initialize the graphics mode. 
(6) Display the screen labels, including the current and position ranges 
and the file names. 
(7) Enter graphics mode and remain there until exited by the operator. 
(8) Return to lamination integrity mode. 
The wedge tightness mode includes three submodes, inspection process, 
graph-stored data, and return to main. As with lamination integrity mode, 
return to main simply returns control to the top level main mode. The 
inspection process submode permits the operator to perform a wedge 
tightness inspection. A wedge tightness inspection is conducted by moving 
indexer 58 to the desired slot and moving indexer plate 60 into 
registration with the slot. 
Carriage 62 is moved along the slot to the desired wedge and the wedge is 
hit by wedge tightness impactor 166 several times. Acoustic data is 
collected, wedge tightness assembly 199 is lowered to its RETRACT 
position, and carriage 62 is moved by computer 52 one-eighth of an inch 
forward and the sequence is repeated seven additional times. 
Accordingly, carriage 62 travels one inch during a complete wedge tightness 
inspection. During the inspection, computer 52 graphs and tabulates on 
screen 48 the gathered acoustic data. During the process, computer 52 
displays a matrix. Each row of the matrix consists of data gathered from 
one of the eight impact sites. 
Computer 52 displays seven values for the time occurring between peaks of 
the acoustic signal created at each impact site. Computer 52 also displays 
a graph showing the acoustic signal generated at the current impact site. 
During initialization of the inspection process, an initialization screen 
is generated that requests whether default values for slot number, wedge 
number, and cursor increment are desired. 
If default values are not desired, the operator enters the slot number, 
wedge number, and cursor increment. Computer 52 then instructs the 
operator to use the jog submode to position carriage 62 under the wedge 
that is to be inspected. 
The graph-stored data submode of the wedge tightness mode is similar to the 
graph-stored data submode of the lamination integrity mode. Upon entering 
the graph-stored data mode, computer 52 asks the operator whether the 
operator wishes to display a directory showing the file names of all wedge 
tightness data previously stored on disk. If so, computer 52 displays the 
directory. If not, the operator enters the file name and indicates whether 
default values for pan increment, cursor increment, or zoom factor are 
desired. If they aren't, the operator may enter the values for pan 
increment, cursor increment, or zoom factor. 
Subsequently, computer 52 displays the matrix of time and current 
information that was gathered previously for a one-inch segment of a 
wedge. The operator may choose which row of data should be displayed on 
the graph. 
The detailed operation of the inspection process submode of the wedge 
tightness mode is presented, in numbered step form, below: 
(1) Display wedge tightness initialization screen. 
(2) Allocate memory in which acoustic data from the wedge tightness channel 
of the A/D convertor will be stored. 
(3) Identify the address at which computer 52 will begin reading data from 
the A/D convertor. 
(4) Set the rate at which the A/D convertor will be triggered to read data 
gathered from acoustic sensor 198. 
(5) Identify which of the nine channels of the A/D convertor will contain 
acoustic data. 
(6) Set the interrupt vector to permit generation of eight interrupts. 
(7) Display the instructions to the operator to move carriage 62 to the 
desired impact sight. 
(8) Allow the operator to use the jog submode to move carriage 62 to the 
first impact sight. 
(9) Create the file name for time data that will be stored on disk. 
(10) Has the operator initiated a stop of the inspection, has an error 
occurred that should stop the inspection, or have all eight impact sites 
been impacted? If so, proceed to Step (12) below. Otherwise, proceed to 
Step (11) below. 
(11) Does the operator wish to continue with wedge tightness data 
collection, move carriage 62, or exit the scan process submode to return 
to the main menu? If the operator wishes to either move carriage 62 or 
return to the main menu, proceed to Step (38) below. Otherwise, proceed to 
Step (12) below. 
(12) Has the operator decided to stop the inspection, has an error 
condition occurred, or have all eight impacts been completed? If so, exit 
the inspection process submode and return to wedge tightness mode. 
Otherwise, proceed to Step (13) below. 
(13) Create a file name for the acoustic data that will be stored on disk. 
(14) Display the template screen, that is, a screen that is blank with the 
exception of the graph axes. 
(15) Disable indexer main drive motor 116 and carriage main drive motor 86 
to prevent indexer 58 and carriage 62 from moving. 
(16) Energize an LED on operator control panel 414 that indicates that the 
wedge tightness inspection is in process. 
(17) Activate wedge tightness assembly lift motor 210 to position impactor 
166 under the wedge. 
(18) Activate impactor 166 several times in succession to cause impactor 
166 to hit the wedge several times. 
(19) Read the acoustic data generated by the impacts into the direct memory 
access area set aside in Step (9). 
(20) Check all digital inputs to the computer. 
(21) Enable the interrupt handler to inform computer 52 that an interrupt 
is imminent. 
(22) Wait until all acoustic data is stored in memory. 
(23) Lower wedge tightness assembly 199. 
(24) Display the acoustic data on the screen, both graphic data and time 
values. 
(25) Save the time values in resident memory. 
(26) Turn off the LED that indicates that wedge tightness data collection 
is complete. 
(27) Save the acoustic data in resident memory. 
(28) Initialize the graphics mode. 
(29) Calculate the screen scales. 
(30) Enter graphics mode and remain there until the operator chooses to 
exit. 
(31) Does the operator wish to proceed to the next impact site, return to 
main mode, or collect acoustic data from the current impact site? If the 
operator wishes to collect more acoustic data from the current impact 
site, or return to the main mode, proceed to Step (35) below. Otherwise, 
proceed to Step (32) below. 
(32) Transfer acoustic data from resident memory to disk. 
(33) Transfer the time values from resident memory to disk. 
(34) Does the operator wish to re-impact the current impact site or return 
to main mode? If the operator wishes to return to main mode, proceed to 
Step (37) below. Otherwise, proceed to Step (36) below. 
(35) Move carriage 62 one-eighth of an inch into the slot. Proceed to Step 
(12) above. 
(36) Permit the operator to move carriage 62 using the jog submode, and 
then proceed to Step (12). inspection process has been completed. Return 
to Step (12) above. 
The details of the graph-stored data submode of the wedge tightness mode 
are presented below in numbered step form: 
(1) Display wedge tightness graph subsystem initialization screen. Provide 
file name directory if desired. 
(2) Display template screen, that is, a blank screen with the exception of 
the graph axes. 
(3) Display the cursor box 
(4) Acquire the graph corresponding to the desired file name from disk and 
read into resident storage. 
(5) Display the graph and enter the graphics mode; remain there until the 
operator exits. 
(6) Return to wedge tightness mode. 
The visual mode includes two submodes, mirror calibration and return to 
main. Return to main permits the operator to return to the top level main 
mode. The mirror calibration submode is used to calibrate mirror 108 
position when the inspection system is first powered up. Since mirror 
rotate encoder 406 provides relative, rather than absolute, position 
information, mirror rotation calibration is required. 
When the operator enters the mirror calibration submode, computer 52 
displays instructions to the operator to move mirror 108 to its clockwise 
limit. When mirror rotation clockwise limit switch is activated, computer 
52 reads the encoder value, which it assumes is the clockwise limit. Upon 
power up, computer 52 prevents the video display from being activated 
without calibrating mirror 108 position. 
The manual mode permits manual operation of carriage 62, indexer 58, and 
indexer plate 60. The manual mode includes six submodes, carriage jog, 
carriage manual, indexer jog, indexer manual, jog indexer plate, and 
return to main. Selecting return to main submode permits the operator to 
return to the to level main mode. Generally, when using any of the jog 
submodes, the apparatus under control can be moved manually by the 
operator. 
The operator control panel includes two jog switches, which are used to jog 
carriage 62, indexer 58, and indexer plate 60. Each switch moves the 
apparatus in a different direction, but only as long as the switch is 
depressed. In the automatic mode, the operator indicates the position to 
which the apparatus should be moved, and computer 52 moves the apparatus 
until the required position is reached. 
Upon entering the carriage jog submode, the computer displays on screen 48 
the current carriage position in inches, the desired carriage velocity in 
inches per second, and instructions pertaining to the direction of 
movement initiated by actuation of each jog switch. The operator enters 
the desired velocity in inches per second. When either jog switch is 
actuated, carriage 62 moves in the commanded direction until the operator 
releases the jog button, until carriage 62 reaches the end of a slot, 
until an emergency stop is generated by the operator at operator control 
panel 414, or until a carriage main drive motor 86 fault occurs. The 
carriage jog LED on operator control panel 414 is energized when carriage 
62 is being jogged. 
The following checks are made anytime carriage 62, indexer 58, or indexer 
plate 60 are moving: 
(1) end of slot front and back carriage sensors 402 and 404; 
(2) emergency stop initiated by operator; 
(3) lamination integrity assembly 143 is lowered; 
(4) wedge tightness assembly 199 is lowered; 
(5) motor faults; 
(6) carriage 62 is not hardware disabled; 
(7) indexer plate 60 is against stator 32 if carriage 62 has been commanded 
to move; 
(8) indexer plate 60 is retracted from stator 32 if indexer 58 has been 
commanded to move. 
The carriage manual submode permits the operator to move carriage 62 
automatically to a desired position. When the carriage manual submode is 
entered, a screen is displayed that requests the position, in inches, to 
which carriage 62 should be moved and the velocity at which carriage 62 
should move to the desired position As computer 52 moves carriage 62 to 
the desired position, a screen is displayed on which carriage 62 position 
and velocity is updated. 
The indexer jog submode permits the operator to move indexer 58 clockwise 
or counterclockwise around the rotor retaining ring. One jog switch on 
operator control panel 414 moves indexer 58 in the clockwise position and 
the remaining jog switch moves indexer 58 in a counterclockwise direction. 
When the operator is jogging indexer 58, computer 52 displays the updated 
position and velocity information. 
The indexer manual submode permits the operator to move indexer 58 by 
identifying the number of the slot to which computer 52 should move 
indexer 58 and the velocity at which indexer 58 should be moved. As 
indexer 58 is moving, computer 52 displays the current slot position and 
the velocity at which indexer 58 is moving. 
The jog indexer plate submode permits the operator to move indexer plate 60 
toward and away from stator 32. Also, a FAST/SLOW speed change capability 
is provided on operator control panel 414, which can be used to move 
indexer plate 60 at either a fast or slow speed. An indicator light is 
energized on operator control panel 414 when indexer plate 60 is being 
moved. 
While for purposes of clarity, the present invention has been described 
with respect to a particular generator which incorporates two sets of 
teeth, it may be appreciated by those skilled in the art, that the present 
invention may be adapted to function in cooperation with a wide variety of 
different models of generators. 
Whereas particular embodiments of the invention have been described for 
purposes of illustration, it will be evident to those skilled in the art 
that numerous variations of the details may be made without departing from 
the invention as defined in the appended claims.