Operating mechanism usable with a vacuum interrupter

An operating mechanism for a vacuum interrupter which includes a spring driven multi-linked system moving the interrupter contacts open or closed with precise, controlled movement to minimize opening rebound, closing rebound and contact opening overtravel. Such a multi-linked system provides high contact separation forces and movement to a specific contact gap while simultaneously loading a closing spring to it's fully charged and latched state. This mechanism provides and maintains full contact pressure from the instant of contact make to the instant of contact separation.

This invention relates to an operating mechanism usable in a circuit 
interrupter of the type utilized in high power distribution systems and 
particularly those interrupters that may be automatically operated to 
permit energization or deenergization in response to abnormal line 
conditions, i.e. excessively high line current, on an automatic local 
basis, or upon command from a remote control center. 
The utilization of vacuum interrupters to provide fast, low, arc energy 
interruption with long contact life requires essential, precise mechanical 
operating characteristics. Contact velocities, minimum rebound on the 
closing and opening operations, high contact pressure in a closed state 
and high separation forces required on opening are all desirable. 
Often a solenoid was directly coupled through a pre-loaded spring member to 
drive vacuum interrupter contact(s) to a spring loaded closed position 
while simultaneously extending the opening spring(s) to a fully charged 
state. For such a device see U.S. Pat. No. 5,175,403, issued Dec. 29, 1992 
to Sidney R. Hamm and Ronald A. Wainio (the latter being one of the joint 
inventors of the present invention) and assigned to the common assignee of 
this invention. In some instances, solenoids of this type were designed 
for a specific voltage rating, thus, making them susceptible to system 
voltage fluctuations directly affecting the contact close operation. The 
directly driven contact member driven through a trip free linkage to close 
may be released to open a partially charged opening spring due to contact 
make occurring prior to the fully closed position being reached. Also, 
inherent in the direct contact drive system to close condition is a 
prolonged delay in reaching the full required contact pressure. 
Another prior art example may be found in the U.S. Pat. No. 3,787,649 
issued to Edwin C. Goodwin, Jr., et al, on Jan. 22, 1974 as well as 
further prior art mechanisms that can be found in U.S. Pat. No. 3,526,735 
issued to K. H. Date on Sep. 1, 1970 and in U.S. Pat. No. 2,804,521 issued 
to Anthony VanRyan et al on Aug. 27, 1957. In the opening sequence of the 
vacuum interrupter contacts in the above described prior art mechanisms, 
full contact pressure is not maintained to contact separation adding to 
the susceptibility of contact welding. Contact separation forces are the 
resultant of the static opening spring forces and any impact energy. For 
example, the opening and closing forces are inter-related, as can be seen 
in the U.S. Pat. No. 3,787,649 to Goodwin, et al. They utilize a preloaded 
pair of co-axially disposed springs 66 and 67 that extend between the base 
of U-shaped stirrup 53 and the head 61 of threaded bolt member 62. The 
springs 66,67 are loaded by adjusting locknuts 69-71 to a preload of 88 
pounds. The movable contacts 42 engage their associated stationary 
contacts 39 when the cam follower rollers are at the midpoint of their 
inclined cam track portions. When the cam follower rollers 57, 57a and 57b 
continue up the cam ramp (after making initial closure of the contacts) 
the contact pressure only varies plus or minus four pounds. This would not 
be adequate to break any contact welds and furthermore these springs would 
not be exerting full pressure at the first instance of contact. This 
closing and opening problem exists in all of the cited prior art and which 
the present inventors are intimately acquainted with since they have 
worked on and with devices covered by the cited art owned by the common 
assignor of the present invention. 
The higher the opening energy the more difficult it is to control contact 
rebound on opening. Some methods used to control rebound on opening were 
dashpots, shock absorbing materials and mechanical catches. In such prior 
art, the static and kinetic opening energy was variable, additionally, 
they utilized mechanical devices to catch and hold the contacts from 
rebounding to a closed condition after opening; dash pots and shock 
absorbing materials were used to dissipate the kinetic opening energy of 
the contact rod assembly. Mechanisms utilizing a variable closing energy 
source contend with variable contact closing speed and energy. 
SUMMARY 
The present invention strives to solve the aforementioned situations by 
providing an operating mechanism designed to overcome each of the problems 
created in the interrupter environment, by an operating mechanism that is 
designed to solve problems such as: (a) providing a consistent, high force 
requirement at contact separation; (b) eliminating contact rebound after 
opening; (c) eliminating excessive contact overtravel on opening; (d) 
eliminating opening spring energy being released from a partially charged 
state; (e) providing a closing energy consistent and independent of any 
variable charging means; (f) providing a minimal time delay in reaching 
full contact pressure after contact make; and (g) eliminating contact 
rebound after contact make on closing. All of these mechanism attributes 
would provide optimum characteristics for an operating mechanism of the 
type contemplated by the present invention for use in a vacuum interrupter 
and would permit superior performance of the switchgear controlled by it. 
For example, the prior art made contact and then increased or loaded the 
contact spring. In the present invention's device, the spring is 
constantly in a preloaded state before contact is made, and the spring 
serves a dual function in that the spring provides closing energy to move 
the contact as well as provide contact pressure when contacts are closed. 
Thus, the present invention provides a stored spring energy operating 
mechanism to open and close linear moving members such as interrupter 
contacts on single or multiphase circuit interrupters. The mechanism 
includes a spring driven multi-linked system moving the interrupter 
contacts open or closed with precise, controlled movement to minimize 
opening rebound, closing rebound and contact opening overtravel. Such a 
multi-linked system provides high contact separation forces and movement 
to a specific contact gap while simultaneously loading a closing spring to 
it's fully charged and latched state. This mechanism provides and 
maintains full contact pressure from the instant of contact make to the 
instant of contact separation. 
A primary key to providing consistent opening and closing operations is the 
use of independent stored spring energy for both the make and the break 
functions and the sequential scheme to charge the opening spring prior to 
releasing a precharged closing spring and subsequent contact closing. 
These and other advantages will become apparent when the specification is 
read in conjunction with the attached drawings, wherein similar parts are 
designated by similar numerals.

DETAILED SPECIFICATION 
Referring to the drawings, and particularly FIGS. 3 through 18, there is 
illustrated a linear operating mechanism, generally designated 20, adapted 
for use with a single phase high voltage circuit interrupter device 22 
positioned within an electrical power distribution system. The major 
components of such an interrupter device 22 include a tank 24; a head 
assembly 26, enclosing the operating mechanism 20 (the primary 
contribution of the present invention); the head 26 also carrying the 
insulated bushings 28,30. The tank 24 also externally carries an 
electronic controller 32 and mounting flanges 36, while the interior 
volume of the tank is filled with transformer type oil, to a level 
substantially indicated by the dashed line 34, as is well known in the 
art. Being a supplier to public utilities, the assignee and the inventors 
abide by the rules relating to "SCADA" defined as: remotely controlled 
"Supervisory Control and Data Acquisition". By following the teachings and 
requirements of SCADA a utility can by remote radio signal interrogate 
and/or change device status. 
Thus, major elements of the interrupter 22 controlled by the operating 
mechanism 20 of the present invention include: a source of motive power, 
i.e., a pot coil assembly 38 accepting a plunger 40 and connecting rod 42; 
an opening and closing solenoid contactor 44; a vacuum interrupter 46 
having associated support members 48; a rod 50 and connector 52 assembly 
provide spring-loaded linear movement through a sealed bellows (not shown) 
for the contacts in the vacuum interrupter 46; and a current transformer 
(not shown) for sensing the line current. 
The closing solenoid contactor 44 is coupled to operating mechanism 20 
through screws 54 and an elongated insulated link 56, with the contactor 
44 being mechanically driven to momentarily energize pot coil 38 to 
provide an upward charging motion through plunger 40 and rod 42. The rod 
42 is flattened at its upper end, as at 43, and apertured to accept pin 58 
(see FIG. 17 for detail). The rod 42 is moved to the position shown in 
FIG. 3 resulting in a disconnection of contactor 44 and immediate 
de-energization of coil 38. 
Operating mechanism 20 coupled through pin 60 to the flattened end 51 of a 
second rod 50 and connector 52 drives the vacuum interrupter 46 contacts, 
not shown, to the open or closed positions, as is known in the art. A 
current transformer, as well known in the art, senses current levels 
passing through the interrupter/recloser sending a proportional signal to 
an electronic control 32, shown generally in FIGS. 1, 2, which initiates 
trip and close signals, which shall be discussed further hereinafter. 
To carry out the proposed solutions set forth herein-above to the seven 
problems enumerated above that face the utility companies, please refer to 
FIGS. 4-19 which disclose the operating mechanism 20 which is the subject 
matter of the present invention. The discussion of the vacuum interrupter 
46, the pot coil 38, the solenoid contactor 44 set forth above is for the 
purpose of providing an environment in which the present invention can be 
utilized. While a single phase high voltage interrupter/recloser is 
described, it must be recognized that the operating mechanism can be also 
readily made available for use with multi-phase circuits. Additionally, it 
also can be utilized in other environments where positive linear actuation 
within designated parameters is required. 
The operating mechanism 20 is generally supported on a round apertured 
plate 70 with a pair of centrally disposed spaced vertically disposed 
brackets or wall-like members 72, 74 each having an outwardly directed 
apertured flange 73, 75, respectively, on which the wall-like members are 
mounted on plate 70 and retained thereon by carriage bolts 76. 
It will be appreciated that while the description below discusses various 
links, pins and levers in the singular, in actuality, in most instances, 
there generally are a pair of elements acting in parallel on opposite 
sides of the centerline between the pair of brackets or wall-like members 
72, 74. This balances the load on the mechanism as well as providing 
multiple points of access to particular forms of motion, i.e., linear, 
rotary and arcuate. 
One of the various assemblies associated with this mechanism is the flux 
tripper assembly 80, best seen in FIG. 5, which includes a stepped plate 
82 mounted on spacers 84 to wall 74 by screws 86; with plate 82 supporting 
electromagnetic release devices FT-1 TRIP designated 90 and FT-2 RE-CLOSE 
designated 92. Devices 90, 92 are used to sequence the mechanism 20 via 
the electronic control logic 32. All of the associated linkage, namely, 
100, 102, 104, 106, 108, 110, 58, 122 and 112A are the actuating mechanism 
linkage for the closing of solenoid contactor 44 by means of link 56. It 
is an over toggle-type mechanism coupled through pin 58 to the toggle 
latch plate assembly 120 which drives spring 122, bracket and pin assembly 
102 through an over-center position of lever assembly 100, and 
particularly the limiting bar 213 that carries the limit pins 212 and 214 
that limit the movement of the link 56 in up and down directions to open 
or close the closing solenoid contactor 44 connected to link 56. The 
contactor 44 would be in the open position with the linkage as shown in 
FIG. 10. 
Referring once again to FIGS. 8-19, which depicts the mechanism 20, 
disposed within the bracket assembly formed by the spaced walls 72, 74, in 
a closed position (the contacts in the vacuum interrupter 46 are closed). 
As best seen schematically in FIG. 10 and FIGS. 16-16A, the spring F is 
retained at its upper end 124 in a fixed inverted centrally apertured 126 
cup-like locating and retaining member 128. As seen in FIGS. 16, 16A and 
FIG. 3, the lower end 130 of the spring F rests within a second cup-like 
member 132 that is secured by suitable fastening means such as a roll pin 
131 along rod 50. Member 132 is accepted piston-like telescopically within 
chamber 134 of an enlarged third cup-like member 136, (shown spaced in the 
illustration for clarity of understanding). Apertured plate member 138 is 
retained by base plate 70 and supports the chambered 134 cup member 136 
which has a central bore 142 that readily accepts the axial movement of 
the lower part 144 of the rod 50 assembly that terminates with connector 
52 and clamp-connector 140, the latter adapted to become fixed to the 
element extending outwardly from vacuum interrupter 46 for actuation of 
the contacts therein. The upper flattened end 51 of rod 50 extends through 
aperture 126 in supporting block 128 into the narrow neck 146 of yoke 148 
until aperture 150 is aligned with apertures 61. An apertured yoke 62 is 
caused to overly the assembly and pin 60 finishes the assembly (see FIGS. 
18, 13 and 13A). Thus, the spring F is pre-loaded between cups 128 and 132 
and will exert a constant downward force, through the rod and connector 
assembly, to the contacts of the vacuum interrupter 46. 
Disposed on opposite outboard sides of the walls 72, 74, are a pair of 
primary storable motive power tension springs 160. Spring 160 exerts a 
force through link 162 and pin 164 to rotate lever 166 clockwise about 
pivot A--A. This rotation is prevented by the latched position of D-shaped 
latch "C" supported within toggle latch assembly 120 (see FIGS. 11, 11A & 
11B) which is also latched in the up position by plunger toggle lever 
assembly 170. Levers 166 are connected to toggle latch assembly 120 
through pin 172, links 174, pin 176, levers 178, latch assembly 180 with 
its contact plate 182, and pin 184. Toggle latch assembly 180 is prevented 
from rotating clockwise about pivot pin 184 by the interference of the 
latch face 182 with the latch C at the surface designated D in FIG. 10. 
The yoke-like link assembly 148 is being forced to a clockwise rotation 
about pivot pin 188 by the downward force exerted by spring F through pin 
60 telescoped within apertures 61 and 150 of the rod and connector 
assembly described previously. Pin 190, links 192 and 194 are connected to 
drive lever assembly 196 to establish the position of pin E. Levers 198 
are adjustably positioned in relation to levers 166 via pin 200 and 
components connector pin 202, adjustment rod 204, spring G, shaft 200 and 
adjustment screw 112. 
Referring now to FIG. 10A, note that the mechanism linkage is shown in the 
open position. This position occurred due to the clockwise rotation of 
latch C clearing the portion D of latch face 182 allowing the clockwise 
rotation of toggle latch assembly 180 about pin 184 by the force exerted 
by spring 160 through pin 176, link 174, pin 172, lever 166, pin 164 and 
links 162. The clockwise rotation of lever 166 about pivot A--A in contact 
with pin E by the contact surface H of lever 166 has positioned pin E to 
the top of the slot J of walls 72 and 74. Drive lever assembly 196 has 
been rotated clockwise about pivot A--A via pin E that it supports. Links 
194 and 192 that are attached to drive lever assembly 196 by means of pins 
K and 208 has driven the right hand end of levers 148, as seen in FIG. 10, 
to an upward position through pin 190. The movement to the up position, as 
seen in FIGS. 10A and 10B, of levers 148 which are connected to rod 50 and 
connector 52 through pin 60 in aperture 61 has moved the contacts of 
vacuum interrupter 46 to an open position and simultaneously loaded spring 
F. 
This contact opening stroke is accomplished in two incremental phases of 
rotation by drive lever assembly 196. The first segment of rotation by 
drive lever assembly 196 has only links 192 in contact with pin 190 to 
drive levers 148 upward beyond the contact separation of the vacuum 
interrupter 46. The position of links 192 and pin 208 are so positioned 
inward to pivot A--A on drive lever 196 to exert a high, consistent 
predetermined force to break any welds that may have occurred at the 
vacuum interrupter contacts. The final segment of rotation by drive lever 
assembly 196 has only links 194 in contact with pin 190 to complete the 
opening stroke of the interrupter contacts to a specific gap. The rotation 
of pin K has been driven to a position, dictated by pin E in slot J, 
beyond a straight line of pin 190 and pivot A--A. Coupled with the 
constant downward pressure exerted by spring F through levers 148 to links 
194 and the smooth transition of pin K through the inline position of pin 
190 and pivot A--A the contact overtravel is minimized. The over-center 
and locked position of pin K and links 194 prevent vacuum interrupter 
contact rebound to close. The above description completes the opening 
sequence of the vacuum interrupter contacts as guided by the operating 
mechanism 20 of the present invention. Referring now to FIG. 10B, the 
operating mechanism is shown open, except toggle latch assembly 120 has 
been rotated to the down position. This movement was initiated by a 
control close signal to energize the electromagnetic release device 92 and 
forcing the plunger toggle lever assembly 170 to rotate clockwise about 
pivot L and out of the over center, locked position. 
It should be interjected at this time that this mechanism contemplates a 
manual form of completing a close operation in the absence of high voltage 
for solenoid 38. There is a closing shaft assembly having spaced elements 
fixedly mounted on shaft M and including at one end a heavy lever 229 
provided with radially spaced bores 230 and 232, with bore 230 fixed to 
shaft M; a pair of small spaced apertured levers 234; and a pair of heavy 
apertured lever arms 236; with an aperture 237 carrying pin 210 for moving 
toggle latch plate assembly 120. The manual aspect is provided by an 
accessory handle (not shown) secured in bore 232 by means of pin 238. 
Thus, the interrupter can be activated to close manually as well as 
electrically/electronically. An external manual operating handle 240, 
shown in FIG. 1, is mechanically linked to parallel operation of close and 
trip solenoids 90 and 92. 
Plunger toggle lever assembly 170, as best seen in FIGS. 15 & 15A, includes 
a pair of spaced levers 220 that are apertured at their free ends to 
accept pin 58 while at their opposite or central end they are provided 
with an oval hole 221. A pair of heavier gauge levers 224 are spaced 
outboard of levers 220 and are joined thereto by pin 222, while at their 
free ends levers 224 carry a fixed pin L which it in turn carries a 
torsion spring P, the free ends of spring P being adapted to contact fixed 
spring anchor 226 and fixed pin 228. 
A downward pressure by a spring about shaft M and the plunger weight on the 
plunger rod assembly 42 by pin 58 forces toggles latch assembly 120 to 
rotate clockwise to the lower limit of pin 210 in slot N. This clockwise 
rotation has rotated latch assembly 180 counterclockwise into a reset 
position with latch C with overtravel to insure positive engagement. The 
clockwise rotation of the toggle latch 120 drives pivot pin 104 down 
beyond the over center position of lever 100 allowing spring 122 to force 
lever 100 to rotate counter clockwise moving the contactor link 56 to the 
up stop position where pin 212 adjoins the lower surface of plate 70. The 
upward movement of the closing solenoid contactor link 56 allows the 
energization of the pot coil assembly 38. This coil energization will 
begin the closing function. Plunger 40 and rod assembly 42 are forced 
upward by the electromagnetic force of the pot coil 38 and being attached 
to toggle latch assembly 120 by pin 58, rotate said assembly 120 
counterclockwise to the latched position of plunger toggle lever assembly 
170 (as seen in FIG. 10) At this latched position the closing solenoid 
contactor 44 has been driven open to de-energize the pot coil assembly 38 
by the associated linkage of 100, 108, 110, 102, 112A, 106, 122 and 104 
being returned to the position shown in FIG. 10. The counterclockwise 
rotation of latch assembly 120 has also urged levers 166 through 
components 180, 184, 178, 174, 176, and 172 to rotate counterclockwise and 
extend springs 160 to a fully charged state. 
Referring back to FIGS. 10 and 10B, levers 198 through attachment to levers 
166 via pin 200 also rotate counterclockwise moving pin 202 into contact 
with detent surface P forcing drive lever assembly 196 and links 194 out 
of the locked position allowing the downward pressure exerted by spring F 
to collapse the multi-linked system of links 194, 192, and drive lever 196 
to the down position shown in section 10--10, i.e. see FIG. 10. Components 
202, 204, 200, 112, and spring G provide adjustment to obtain the 
mechanical sequence of remaking the plunger toggle lever assembly 170 to 
its overcenter position, followed by closing of the vacuum interrupter 
contacts. 
Referring to FIG. 10 as well as FIGS. 16, 16A, spring F is exerting a force 
to the piston 132 and has moved the contacts of the vacuum interrupter 46 
to a closed position. Having a spring F loaded to a predetermined 
pressure, the force applied at contact make is instantaneous without 
delay. This time is critical in minimizing contact rebound, blow open, and 
contact welding upon initial contact make especially at high fault current 
levels. The contact closing velocity has been modified to reduce the 
impact energy at the interrupter contacts via piston 132 and piston 
chamber 134, utilizing transformer oil in chamber 134 to provide hydraulic 
dampening. The piston 132 is directly attached to the contact rod 50 and 
the piston chamber 134 is attached to the base plate 70 by means of 
retaining plate 138 (see FIGS. 3, 16, & 16A). 
A verbal schematic description of the procedure followed by the mechanism 
20 that hopefully will simplify its operation follows: First, assuming the 
mechanism is in a "closed" position and the vacuum interrupter contacts 
were carrying the load current and an over current condition exists on the 
line the following would occur: The electronic control 32 under this 
condition would issue a trip signal to one of the two flux shift trippers, 
that being the trip flux tripper 90. That releases the toggle latch 120 
allowing the opening springs 160 which were in a fully loaded state to 
simultaneously pull the contacts of the vacuum interrupter 46 to the open 
position. That is, the opening springs 160 will discharge and 
simultaneously open the vacuum interrupter contacts as well as rearming 
the closing spring F. At that point in time the electronic control 32 from 
various sensing positions in the mechanism will realize that the contacts 
of the vacuum interrupter are indeed in the open position and the fault 
has been interrupted. There is no load current, the control 32 then 
decides to issue a reclosing signal to the closing flux shift tripper, 
recloser 92. When the closing flux shift tripper 92 is energized it 
essentially releases a toggle latch C on the toggle latch assembly 120 
which allows the plunger to drop. When the main pot coil plunger drops it 
overtoggles the pot switch linkage closing our high voltage contactor 44 
of the pot switch linkage. That energizes the high voltage closing coil 
38, the high voltage closing coil then drives the closing coil plunger 40 
and rod 42 back upwards in an upward motion (as seen in the drawing). The 
opening springs 160 again being recharged and as that closing stroke is 
continuing near the end of the stroke, the hot switch 44 is being biased 
back to the open position which de-energizes the high voltage closing 
solenoid 38. The hot switch 44 now is in the open condition, the toggle 
assembly 120 is being latched in the full upward position, the opening 
springs 160 are fully armed and at the very end of the plunger stroke 42, 
through the mobile link system, over toggles the closing spring F which 
was fully charged as discussed previously and that drives the vacuum 
interrupter 46 contacts back closed again. At this point in time we are 
back on line again. If there are one or more continued faults, the device 
then goes through a program sequence and the control 32, if the fault is 
permanent, counts the number of sequences and when a predetermined number 
is reached the electronic control 32 decides it's permanent then we stand 
a lock out condition which just simply means the electronics gives no more 
closing signals. 
Thusly, the closing spring F and the opening spring 160 are both brought to 
fully loaded condition before the opposite number is activated, namely, 
that in the event that some line activity takes place either at or just 
before the closing function the opening function spring 160 has already 
been fully loaded. Similarly; the closing function spring F has been fully 
loaded prior to opening spring 160 being released. Whereas, the prior art 
cited above do not have this luxury since these closing and opening 
functions in those devices all require some secondary action. Either the 
closing of the contacts is not at instantaneous full pressure, or, the 
separation of the contacts is not at full power and capable of opening up 
welded condition contacts. 
Thus, structure and function have been provided to support the allegation 
that this invention solves the seven problems originally proffered.