Apparatus for Starting Electric Motors.
Year: 1898

page_text: Date of Application, 30th Sept., 1898-Accepted, 26th Nov., 1898
Apparatus for Starting Electric Motors.
I, GEORGE BULLOCK, Electrical Engineer, of No. 220, Broadway, in the City,
County, and State of New York, United States of America, do hereby declare the
nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement:-
:
My invention relates to apparatus for starting electric motors. It is particularly.
applicable for use in connection with inotors which are operated from supply circuits
of approximately constant potentials, and which are used for the purpose of driving.
that class of machinery. wherein the moment necessary to start it in motion exceeds.
that necessary to accelerate and maintain motion. The object of the invention is to
construct apparatus which shall utilize the current to the best advantage and start
the motor evenly and without shock.
In instances of running such machinery by steam engines it is customary to.
interpose a train of gears between the power supply and the shaft of the machine to.
be started, the gearing being adapted to multiply the moment delivered to the shaft:
of the machine to be started in proportion to the ratio of the gearing, and to throw
out this gear when the machinery gets started in motion. I propose to accomplish
a substantially similar result electrically when the machinery to be started is to use:
electricity as a motive power through the medium of an electric motor. In carrying
out my invention I interpose in the electric circuit, apparatus for producing a fixed
multiplication of the currents of the supply circuit, which inultiplied current is used
in starting the electric motor. After the machinery gets started in motion I with-
draw the current multiplier, or electric gearing, from the circuit. This multiplying
of the current may be accomplished by transformation, and for this purpose any
suitable converter may be used. To accomplish best results, however, the primary:
and secondary windings should have a definite and constant inductive relation.
Both windings should be in the same magnetic circuit, in which case the ratio or.
multiplying power of the current will be approximately the ratio of secondary.
turns, in its same way as with mechanical gearing, within the multiplied power of
the moment is the ratio of the number of teeth one of the gear to that of the other.
with which it engages.
The invention is designed for use upon either continuous or alternating currents.
When continuous currents are used, the motor should, in order to produce best
results, to be a continuous current inotor, and the current be changed to alternating
currents for the purpose of transformation, and the transformed currents then
rectified to continuous currents before reaching the motor, by any well known.
device for transforming continuous currents. Whether used with continuous or
alternating currents the converter may consist of any device, rotary or otherwise,
for multiplying or changing the current according to the nature and requirements
of the particular machine to which the invention is to be applied, it being here noted.
that I have used the term "converter" herein in the broadest sense, to include all
such devices.
The invention will be described more in detail with reference to the accompanying
drawings, in which

page_text: Figs. 2, 3 and 4 are respectively diagrams of the metallic circuits of the apparatus
shown in Fig. 1 at starting, intermediate and final position.
Fig. 5 is a conventional view of a similar apparatus showing a different, arrange-
ment of circuits, and
Figs. 6 and 7 are respectively diagrams of the metallic circuits of Fig. 5 at starting
and final positions.
Referring to the drawing, 1 and 2 represent the terminals of the supply circuit
froin which current is to be drawn to operate the motor, B represents the motor to
be started, C represents the converter, or current multiplier, and A represents a
controlling rheostat, to be hereinafter described, adapted to throw the converter into
and out of circuit with the notor. It will become apparent in following out the
description of my invention that apparatus embodying the same may be constructed
in which may be used any common type of rheostats switching devices, but I have
here shown and described a rheostat and switching device in which all the various
operations essential to the carrying out of the invention are combined in one
apparatus, and which has been found by me to be the best adapted to perform the
same. It is to be understood, however, that I do not limit myself to the device bere
shown, but consider that all equivalents shall be embraced within the description
and claims of my invention as hereinafter set forth. The contact blade of the
controller A is represented by a, the latter being a prolongation of the lever a¹, and
separated therefrom by insulation a². The controller has three contact 'bars, 4, 5
and 6, the former being continuous throughout its length and connected by wire 3
to terminal 1. Bars 5 and 6 are each divided into a plurality of contact plates 61, 7,
8, 9, 10, 11, 12 and 13, 14, 15, 16, 16, 17, 18, as shown in the drawing. The
contact plates in bars 5 and 6 are respectively connected to resistance coils 19, 20,
21, 22, 23, 24, which resistances are gradually cut out of circuit as contact blade a is.
moved from plate 7 to plate 12, and from plate 13 to plate 18. Switchblade 25 is
insulated froin blade a, but is arranged to move by the latter so that as blade a
moves to one side or the other of the centre 'line of bars 5 and 6, the switchblade
will move to the opposite side to make contact with one of the two contact plates 26
and 27. A wire 28 leads from contact plate 26 to the primary of the converter C
and from thence a wire 29 leads to contact point 30. 31 and 32 are contact
points arranged. in line with point 30. A blade 33 is mounted upon stud a³,
upon which lever a¹ is mounted, and is insulated from said stud. This blade is
adapted to make contact with and join points 30, 31 and 32. A hook 34, to be
hereinafter described, is adapted to engage with a stud blade 33 and hold the same
normally in contact with the points 30, 31 and 32, and a spring 35 is adapted to
withdraw the blade from engagement with the contact point when the hook is
released. A wire 38 leads to coil 39 of a magnet 40, to the end of which magnet,
hook 34 is hinged. A spring 41 tends to hold the hook away from the magnet, and
out of engagement with blade 33, but when current is flowing through the coil of the
magnet the latter will become energized and hold the hook in engagement with the
blade 33.
In the apparatus shown in Fig. 1 a wire 42 leads from the magnet 40 to the
secondary of the converter C, and from thence a wire 43 leads to motor B. From
motor B wire 44 leads to wire 37, the latter leading to the terminal 2.
A wire 36 connects wire 44 with the contact point 31. Therefore when current
is flowing through the primary of the converter a current will be induced in the
secondary of the converter the metallic circuit of which will include-wire 43 motor B,
wires 44 and 36, contact point 31, blade 33, contact point 32, wire 38, coil 39,
wire 42 and the converter.
The blade 33 is provided with a lug 45 adapted to engage with a similar lug 46
upon lever a¹, whereby.in moving the lever so that the blade a will be at the limit
of its movement on contact plate 61 the lugs will have engaged and moved blade 33
over into engagement with the contact points 30, 31 and 32. The upper side of the
hook 34 is suitably curved in order that a spring catch 49 upon lever a¹ will bear.
upon the upper side of the hook 34 when the lever a¹ is adjacent to it, and thus hold

page_text: the hook in engagement with blade 33 notwithstanding there may be no current in
the magnet.
A contact point 50 is connected with wire 48 by a wire 51, and a contact point 53
is connected with wire 36 by a wire 54. A plate 52 upon lever a¹, insulated there-
from, is adapted to connect points 50 and 53, in order that in stopping the device a.
local circuit of the motor may be closed to brake the motor.
The.
The operation of the apparatus above described, is substantially as follows:
Before starting the lever is brought around to the position at which blade a
is in contact with contact point 6¹. The moving of the lever to this position..
has brought the lugs 45 and 46 in contact and moved blade 33 into contact with
the points 30, 31 and 32, and the pressure of the spring catch 49 upon the
upper side of hook 34 holds the latter in engagement with the blade 33.
moving of the lever has also moved the switchpoint 25 into contact with plate 26.
The operation of starting is commenced by moving blade a into contact with
contact plate 7.. In this position the metallic circuit will be substantially as shown
in Fig. 2, in which case a small current from the supply circuit produces an increased
current in the induced circuit, thus supplying the armature of the notor with.
current of low potential but.large amperage. The lever is then moved further over,
successively cutting out the resistances 19, 20, etc., increasing the strength of the
current, until the. end of the blarle moves the point 25 over upon contact 27, which
changes the metallic circuit to substantially that shown in Fig. 3, in which the
induced current is still operative, but the current from the supply circuit is
introduced through the resistances directly into the motor. The lever being
moved still further to cut out the resistance in the supply circuit the induced
current will be decreased as that of the supply circuit is increased, until at
some point the strength of the magnetism due to the induced current will
be overcome by the spring and the hook 34 will be released from the..
magnet, allowing blade 33 to be drawn out of contact with points 30, 31 and 32,
by its spring, thus opening the induced circuit and effectually. removing the converter
from the motor circuit. The point at which the induced circuit will be opened. will
of course vary according to the moment necessary to start the notor, and will occur
at some intermediate speed between rest and full speed.
It will also be seen that the above described apparatus is capable of considerable
modification, variation, etc., without departing from my invention. The form of.
windings of the apparatus, and the ratio of the current multiplier, or converter,
in particular, should be determined and arranged to suit each individual apparatus.
according to the work which it is designed to perform. I therefore desire it to be
understood that I have here shown conventional forms of the various parts of the
apparatus for the purpose of indicating that any suitable devices for performing the
functions herein described for those parts may be used in place of the various parts.
here shown, and that I do not limit myself herein to the precise construction and
arrangement shown and described, but consider as, within the scope and terms of
the invention all equivalents and modifications of the various parts when used in
combination as lierein set forth.
In Fig. I have shown a modification of my invention adapted to a different
arrangement of connections. In this construction a wire 43 connects contact
point 31 with the inotor B, and a wire 42 connects the secondary of the converter
with the terminal 2. This, in the operation of the device, will change the circuits
so that in starting position they will be as shown in diagram in Fig. 6, and in final
position as shown in Fig. 7. In this instance the supply circuit and the converter
circuit are combined at the motor, although independent at other points of the.
system.
Having now particularly described and ascertained the nature of my said inven- .
tion and in what manner the same is to be performed, I declare that what I
claim is
:

page_text: connecting the motor with the supply circuit, a converter in circuit with the motor
and with the supply circuit, and means for breaking the converter circuit at an
intermediate speed of the motor, substantially as described.
2. The combination with an electric motor, of a supply circuit, means for connecting
the motor with the supply circuit, a converter in circuit with the motor and with the
supply circuit, and means for automatically breaking the converter circuit at an
intermediate speed of the motor, substantially as described.
3. The combination with an electric motor, of a supply circuit, means for con-
necting the motor with the supply circuit, a controlling rheostat in said supply
circuit, a converter in circuit with the motor and with said supply circuit, and
means. for breaking the converter circuit at an intermediate speed of the motor,
substantially as described.
4. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, a controlling rheostat in said circuit,
a converter, means for interposing said converter in said circuit intermediate the
rheostat and notor, and means for withdrawing said converter from the circuit,
substantially as described.
5. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, a converter in circuit with the
motor and with the supply circuit, means for varying the strength of the current
from the converter, and means for cutting the converter out of circuit at an inter-
mediate speed of the motor, substantially as described.
6. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, a converter in circuit with the
motor and with the supply circuit, and means for varying the relative values of
the currents from the supply circuit and converter circuit, substantially as
described.
7. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, à converter in circuit with the
motor and with the supply circuit, means for varying the relative values of the
currents from the supply circuit and converter circuit, and meaus for cutting said
converter out of circuit, substantially as described.
8. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, a converter in circuit with the
motor, a source of current supply connected with the converter, and means for breaking
the converter circuit, substantially as described.
9. The combination with an electric motor, of a supply circuit, a local
circuit induced from said supply circuit, means for combining the current from
the induced circuit with that from the supply circuit, and means for supplying said
combined currents to the armature of the motor, substantially as described.
10. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, a converter in circuit with the
motor, a source of current supply connected with the converter, means for combining
the current from the converter circuit with that from the supply circuit, and means
for supplying said combined currents to the arinature of the motor substantially as
described.
11. The combination with an electric motor, of a supply circuit, a local circuit
induced from said supply circuit, means for directing current from said induced
circuit into the arinature of the motor, means for directing the current from the
supply circuit into the armature of the motor, and means for varying the relative
values of the currents from the induced circuit and from the supply circuit,
substantially as described.
12. The combination with an electric motor, of a supply circuit, a local circuit
induced from said supply circuit, means for combining the current from the induced
circuit with that from the supply circuit, means for varying their relative values,
and means for supplying said combined currents to the armature of the motor,
substantially as described.

page_text: 13. The combination with an electric motor, of a supply circuit, a local circuit induced
from said supply circuit, both of said circuits being connected with the armature
of the motor, a rheostat in the supply circuit, and a switch adapted to open and
close said induced circuit, substantially as described.
14. The combination with an electric motor, of a supply circuit, a local circuit
induced from said supply circuit, both of said circuits being connected with the
armature of the motor, and an automatic switch adapted to open said induced
circuit at an intermediate speed of the motor, substantially as described.
15. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, a local circuit induced from said
supply circuit and connected with the motor, a rheostat in the supply circuit, a
switch adapted to open said induced circuit magnet controlled by said induced circuit
and adapted to hold said switch closed, means for varying the relative values of the
currents from the supply circuit and from the induced circuit, and means for
opening said switch when the strength of said magnet falls below a predetermined
point, substantially as described.
16. The combination with an electric motor, of a supply circuit, a converting
device, two sets of resistances, one in circuit with the motor and the other in circuit
with the converting device, and a switch connected with the supply circuit and
adapted to make contact with the respective sets of resistances, substantially as
described.
17. The combination with an electric motor, of a supply circuit, a converting
device, two sets of resistances, one in circuit with the motor and the other in circuit.
with the converting device, a switch connected with the supply circuit and
adapted to make contact first with the resistance in circuit with the converting
device then with the resistance in circuit with the motor, and means for cutting the
converting device out of circuit, substantially as described.
18. The combination with an electric motor, of a supply circuit, means for
connecting the motor with the supply circuit, a local circuit induced from said
supply circuit, a controlling device comprising a rheostat in said supply circuit, an
operating lever adapted to control the same, and a switch in said induced current
adapted to be closed by the action of said lever and released when the induced
current falls below a predetermined strength, substanțially as described.
Dated this 18th day of September 1898