Improvements in Apparatus for Starting Electric Motors.
Year: 1898

page_text: UUMILIE DIECITICA ITUN.
Improvements in Apparatus for Starting Electric Motors.
I, JAMES BURKE, of 23/24, Oudenarderstrasse, Berlin, N, Germany, Electrician,
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 motors which are operated from supply
circuits of approximately constant potential, 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 accom-
plish 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 current from the supply circuit, which
multiplied current is used in starting the electric motor. After the machinery
gets started in motion I withdraw 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 the 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 to primary turns, in the same
way as with mechanical gearing wherein the multiplying power of the moment
is the ratio of the number of teeth of one gear to that of the other with which it
engages.
The invention is designed for use with either continuous or alternating cur-
rents. When continuous currents are used, the motor should, in order to produce
the best results, be a continuous current motor, and the currents be changed to
alternating currents for the purpose of transformation, and the transformed cur-
rents then rectified to continuous currents before reaching the motor, by any well
known device for transforming continuous currents. Whether used with con-
tinuous 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 its broadest"
sense, to include all such devices.

page_text: The invention will be described more in detail with reference to the accom-
panying drawings, in which
Fig. 1 represents diagrammatically an apparatus embodying my invention,
Figs. 2, 3, and 4 are respectively diagrams of the metallic circuits of the
apparatus shown in Fig. 1 at the starting, intermediate and final positions.
Fig. 5 is a diagrammatic view of a similar apparatus showing a different
arrangement of circuits, and
Figs. 6, 7 and 8 are respectively diagrams of the metallic circuits of Fig. 5 at
the starting, intermediate and final positions.
Referring to the drawings, 1 and 2 represent the terminals of the supply
circuit, from 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 motor. 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 and
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 here shown, but consider all equivalents
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 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 6, 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 resis
tances are gradually cut out of circuit as contact blade a is moved from plate?
to plate 12, and from plate 13 to plate 18. Switchblade 25 is insulated from
blade but is arranged to be moved by the latter so that as blade « moves to
one side or the other of the centre line of bars 5 and 6, the switch blade 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 the stud, a³, upon
which the lever a is mounted, and is insulated from the main 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 on the blade 33 and hold
the same normally in contact with the points 30, 31 and 32, and spring 35 is
adapted to withdraw the blade from engagement with the contact point when the
hook is released. A wire 38 leads to the 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 a whereby in moving the lever so that the blade a will be at the

page_text: The
limit of its movement on contact plate 62 the lugs will have engaged and moved
blade 33 over into engagement with the contact points 30, 31 and 32.
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 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
therefrom, 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 opera-
tion 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 6. 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. The moving of the lever has
also moved the switch point 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 motor
with current of low potential, but large amperage. The lever is then
moved further over, successively cutting out the resistances 19 20 etc. in-
creasing the strength of the current, until the end of the blade 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
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 effec-
tually 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 neces-
sary to start the motor, and will occur at some intermediate speed between rest
and full speed.
to
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. Also instead of the set
of resistance coils 19-24, which is included sometimes in the one and sometimes
in the other current, circuit, two different sets of resistance coils may be employed.
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 suit-
able 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 herein set forth.
In Fig. 5 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 motor 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. S. In this instance the supply circuit and

page_text: 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 the said in-
vention, and in what manner the same is to be performed, I declare that what I
claim. is:
1. 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 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
connecting the motor with the supply circuit, a controlling rheostat in said
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.
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 inter-
mediate the rheostat and motor, 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
intermediate 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, a 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 means for cutting
said converter out of circuit, substantially as described.
S. 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 com-
bining the current from the converter circuit with that from the supply circuit,
and means for supplying said combined currents to the armature 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 armature of the motor, means for directing the current from the
supply circuit into the armature of the motor, and means for varying the relative.

page_text: values of the currents from the induced circuit and from the supply circuit sub-
stantially 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 in-
duced 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.
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, a 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 circuits 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 and 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
circuit adapted to be closed by action of said lever and released when the induced
current falls below a predetermined strength, substantially as described,
F. WISE HOWORTH,
46, Lincoln's Inn Fields, London, W.C., Agent for the Applicant.