US1112784A - Means for controlling electric currents. - Google Patents

Description

l B.L.GALE,SL MEANS FOR GONTROLLNG ELECTRIC GURRENTS.

APPLIUTION FILED DEG. 1B, 1905.

r1,1 12,784. Patented 0st. 191@ UNITED STATES .it-@TENT onnion.

ERNEST L. GALE, SR., 0F YONKEBS, NEW YORK, ASSIGNOR T() OTIS ELEVATOR COIXI PANY, OF JERSEY CITY, NEW JERSEY, A GOR-PORATON OF NEW JERSEY.

MEANS FOR CONTROLLING ELECTRIC CU'RRENTS.

Original application filed May 1, 190.5, Serial No. 258,378.

f T0 all 'whom t may concern s Be it known that I, ERNEST L. GALE, Sr., a citizen of the United States, residing in the city of Yonkers, in the county of Westchester and State of New York, have invented a new and useful Improvement in Means for Controlling Electric Currents, of which the following is a specification.

My invention relates to apparatus for controlling elect-ric currents, and more particularly'those used for starting and controlling electric motors.

This application is a division of my copending application Serial No. 258,378, filed May l, 1905, for an improvement in current controlling apparatus. v One of the objects of my invention is the provision of simple and eilicient means for starting an electricmotor.

Another object of my invention is the provision of improved and simplified construction for starting and operating elec- Y tric motors with minimum consumption of current. Y ther ob]ccts of the present invention will appear hereinafter, the novel combinations of elements being pointed out in the claims.:

The accompanying drawing is a diagrammatic view illustrating one form of my in-A vention. It designates a controlling device, as for example, an armature of a direct current motor, I have'herein shown, by Way ,i of illust ation merely, 'an armature of a diture 1 and the resistance 454B. The mains.

rect current motor, but I wish it to be understood that the term motor used in the claims is intended to cover a reciprocating motor such as an electromagnet, as Well as a rotary motor, either direct current or alterna-ting current.

4A and 4B designa-te a resistance element which is shown as an ohmic resistance, but may be inductive or capacity or other means for opposing or checking the flow of current, orif desired may be comprised of an ohmic resistance alone or combined with an inductance. This resistance, element is proportioned in a Well-known Way to prevent too much current from flowing through the motor upon starting the same. A switch 10-is placed in series with the motor-armaare designated by -land and are 'connected directly to thev meter-armature and the switch 1,0, respectiYely, -asjjshown. The

Specification of Letters Patent.

Patented Get. 6, 1914. Divided and this application iled December 1g,

serial No. 292,120.

shunt field 9 may be connected to 'the positive main to the left of the motor-armature, and the motor-armatlue circuit between the resistance element 4^, el and the switch l0. rlhc controlling circuit is in parallel with the resistance LA and 4B andincludes the eXtra icld 9^, solenoids 2f# and 2B, and a hand operated switch 3. The solenoids 2A, 2B are adapted when energized to. lift their cores with the connected contact makers 7, 7', and thus insert a resistance 4A, ein, in circuit with the motor armature l.

ln starting themotor, the switch l0 being opened, and the switch 3 closed, the mainline current is turned on. so that current will flow through the solenoids 2A, 2B, to excite the same and eilect the lifting of their cores. The controlling circuit is preferably of comparatively hiOh resistance and the current which passes through it will not be of suiiicient strength to have any appreciable cl'ect upon thc motor-armature. ter the solenoids 2A, 2B have operated, the switch l0 is closed. IThis closes a circuit to the shuntield 9 and also through the starting resistance 4A, 4B, which is in series with the motorarmature l. It Will be seen that the controlling circuit comprising the solenoids 2A, 2B and the extra field 9^ is connected in shunt to the resistance elements 4A and ein. After the motor starts, and its countcr-electro-motiveforce gradually increases to gradually decrease the current flow through the starting resistance, the potential between the points ll and l2 gradually diminishes, until the current in the controlling circuit is weakened thereby to such'an extent that the s olenoids 2A, 2B release their cores and allow the bridge pieces or contact makers, 7, 7 to dropv thus short-cireuiting the starting resistance. This will allow the armature to receive theull potential of the line so that the motor will run to full speed. rlhe controlling v circuit, therefore, is itself controlled by the varying `potential resistance 4A and 45B. lVhen the contact makers?, Tf drop they also short-circuit the controlling circuit ine This I consider a valuable feature of my in-l i vention. In other words, it is the variation of potential across the resistance element that is utilized to influence the controlling circuit and tc cause the same to actuate and release means for varying the armature resistance or other current-opposing means.

I have shown two solenoids 2A,`2B, for controlling the starting resistance, butl it'will be understood that a greater or less number may be employed if desired with a corresponding number of sections of resistance. The sol'enoids are preferably made to operate at different potentials. tion may be eiiected in various ways. 'As shown, the solenoid 2A has a smaller number of turns than the solenoid 2B. The solenoid 1 2A will therefore release its core before the solenoid 2B releases its core; y ItwiIl be seenthat when the motor is started up with the",l resistance element in circuit, the extraiield 9A will be fully energized since it receives current depending upon the potential across the resistance element or between the points '11 and l2. During the operation of this system, this potential gradually diminishes until it is practically negligible and therefore the current through this extra iield 9A will die out as the motor approaches full speed.

` The magnetic iield coil of the motor may be excited in any desired manner and may comprise, for example, a shunt field coil 9 connected across the mains as shown. This by itself will maintain the magnetic 'eld at its normal strength. When the main cirmcuit is closed to start the motor. the extra field will increase the strength of the magnetic ieldt'due'tp the shunt 'coil 9, and this will increase 'fthe starting torque of the motor or make it possible to have the same starting torque with less current consumption in the armature. As the motor increases in speed, this eXtra field gradually diminishes in strength, and the decrease in strength ell'ects a gradual increase in speed of the motor vbecause as the opposition or resistance is reduced the current inthe extra field is gradually and automatically reduced to practically zero. This, it will be noti/ced, is accomplished without any additional switches, lwhich, is an advantage over present practice.

It isy evident thatv the motor may be started' and stopped/by the operation of the,l

switch 10 alone if the continuity of the cbntrolling circuit in series with the armaturey between the positive and negative -`mains' is not interrupted, and the controlling circuit is of suihcient resistance to prevent enough.` current from iiowing through the armature to ei'ect the starting of the same. For instance, switch 3 mayV be kept closed and the sou`rce=-of supply cutv off from the motor and the switch 10 opened. Now when the source of current supply is connected to the motor the controllingcircuit 'will imheretofore explained. In the event of deu-I pending .upon the initial closure of a switch 'connecting the source of current supply to the positive and negative mains leading lfrom the motor apparatus, the switch 3 may bev entirely omitted or kept closed and only the switch 10 closed afterthe positive and negative terminals have been connected to the source of supply. This is true Whether the motor armature starts up at once as soon as current flows in series through the motor i armature and the controlli g circuit.

Anyjvsuitable form of electromagnet may be usedin the controlling circuit, but I have shown by Way 'of illustration, a suitable form of elcctromagnet in my co-pendlng application 258,378, filed Mayl, 1905, of which this applicationl is a division.

Without limiting myself to any of the details of constructiony or arrangement of parts as herein disclosed, what I claim and desire to have protected bylietters Patent is:

1. In motor controlling apparatus, the combination with a motor-armature and a eld circuit, of starting'resistance, electromagnetic switches initially holding said starting resistance cut out, an extra eld winding in series with the electro-magnets of said switches in a circuit in parallel to said starting resistance, and Switching mechanism for closing said circuits.4

' 2. In motor controlling apparatus, the combination with a. motor-armature of starting resistance in series therewith, a eld winding for said motor, an extra field winding, a controlling circuit including said extra field winding, an electro-magnet in said controlling circuit, and means operated by said electro-magnet forlcontrolling said starting resistance.

3. In current, controlling apparatus. .the

ance, a series of electro-magnets in said controlling circuit each having a single winding and automatically operated according to the varying potential across said starting resistance to control the said switches, an extra field winding in series with said electro- 'magnets, and means for controlling said electro-magnets.

4.- In motor controlling apparatus, the combination witha motor-armature,v of a iield circuit, starting resistance in'series with the motor-armature, a switch for controlling said starting resistance, an electroseries'of switches connected to Said resist-Y magnet'for operating said switch, a controlling. circuit connected across said start- .ing resistance and including said electro- -feld circuit, of starting resistance, an extra field winding, switches initially short-'circuiting said starting resistance, electrol magnets for operating said switches to insert said resistance when energized and for then. permitting the switches to close successively to glually cut out said resistance as the arma increases in speed, a switch forclosing the circuit including said extra field winding, and said electroimagnets in series with each other in a circuit in parallel with the starting resistance and -in series with the motor armature, and 'a switch for closing the main armature circuit including the motor armaturel and said starting resistance in series withieach other.

6. In motor controlling apparatus, the combination with a motor-armature, of a shunt field winding therefor, starting resistance in series with the motor-armature and divided into sections, a plurality of switches connected to said sections, a. plurality of electro-magnets one for each of said switchesban extrafield winding in series with said electro-magnets in a control'- lding circuit across said starting resistance, a switch for initially closing the controlling circuit to open the switches and insert the starting resistance, and an additional switch for closing the main armature circuit, the electro-magnets then permitting switches to close again to short-circuit the starting resistance.

In testimony whereof, I have signed my name to this specification in the presence of two subscribing witnesses.

.. ERNEST L. GALE, SR.

Witnesses:

CHARLES M. NIssEN, ALFRED C. BEGHE'T;

said

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