US2157640A - Universal motor speed governor - Google Patents

Universal motor speed governor Download PDF

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Publication number
US2157640A
US2157640A US215426A US21542638A US2157640A US 2157640 A US2157640 A US 2157640A US 215426 A US215426 A US 215426A US 21542638 A US21542638 A US 21542638A US 2157640 A US2157640 A US 2157640A
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United States
Prior art keywords
contacts
motor
wire
speed
contact
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Expired - Lifetime
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US215426A
Inventor
Stanley H Swarthout
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Motors Liquidation Co
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Motors Liquidation Co
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Publication date
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Priority to US215426A priority Critical patent/US2157640A/en
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Publication of US2157640A publication Critical patent/US2157640A/en
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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02PCONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P25/00Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details
    • H02P25/16Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring
    • H02P25/18Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays
    • H02P25/182Arrangements or methods for the control of AC motors characterised by the kind of AC motor or by structural details characterised by the circuit arrangement or by the kind of wiring with arrangements for switching the windings, e.g. with mechanical switches or relays whereby the speed is regulated by using centrifucal devices, e.g. switch, resistor
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S388/00Electricity: motor control systems
    • Y10S388/923Specific feedback condition or device
    • Y10S388/924Centrifugal device, e.g. governor
    • Y10S388/925Centrifugal device, e.g. governor including contacts which open and close motor circuit

Description

May 9, 1939. s. H. SWARTHOUT 2,157,640
UNIVERSAL MOTOR SPEED GOVERNOR Filed June 23,.1958
NTOR
BY m 4- ATTORNEY/4 P atented May 9, 1939 UNITED STATES PATENT OFFICE to General Motors Corporation,
Delaware a corporation of Application June 23,
3 Claims.
This invention relates to a universal electric motor, that is, a motor which will work either on alternating current or direct current circuits.
More particularly the invention relates to a speed 5 governor for universal electric motors.
The present invention is applicable to speed governors of the make and break contact type and is particularly useful on governors where the contact separation or the wiping action of the contact is small. Under these conditions and where close regulation of the speed is required it will be seen that the space between the contacts must be maintained. It is well known that on contacts interrupting a direct current circuit the positive contact is liable to form a crater or pit and the negative contact will in turn build up in the form of a cone or needle or other shape, this action being progressive. On contacts interrupting an alternating current circuit, since the current is reversed every half cycle, there is no chance for either contact to build up or pit and consequently both contacts wear down evenly. The pitting of the one contact and the building up on the other which ordinarily occurs with direct current use may seriously affect the regulation of the motor speed; therefore, it is very desirable to eliminate the transfer of material between the contacts to obtain uniform and equal wear on both contacts.
The object of the present invention is to provide means for obtaining uniform wear of the contacts on a speed governor or motor regardless of whether it is used on direct or alternating current.
Further objects and advantages of the present' invention will be apparent from the following description, reference being had to the accompanying drawing wherein a preferred embodiment of the present invention is clearly shown.
The figure of the drawing is a wiring diagram embodying the present invention.
One application of the electric motor embodying the present invention is to drive a direct current generator for supplying current to the power amplifier of a motion picture outfit which incorporates sound effects. As the motor circuit embodying the present invention is capable of other uses the particular load which is applied to the motor is not shown in the figure of the drawing.
In the drawing 23 designates a universal motor 30 of the series type having one of its brushes 2| connected with the series field winding 23 which is connected with line wire 24. The motor armature shaft 2! drives a disk 33 on one side of which are mounted two speed-responsive circuit break- 3 era 3| and 32, which are similar in construction.
Detroit, Mich.,
1938, Serial No. 215,426 (or. 171-312) Circuit breaker 3| comprises a relatively stationary contact 33 cooperating with a relatively movable contact 34. Contact 33 is mounted on a plate 35 supported by leaf spring 33 attached to a bracket 31, the disk 30. Contact 34 is attached to a pair of plates 33 supported upon a leaf spring 33 attached to a bracket 40 which is insulatingly supported by the disk 30. The plates 38serve as a weight which is affected by centrifugal force to cause it to move outwardly from the shaft 25 so as to separate the contact 34 from the contact 33 at a predetermined speed. Spring 39 biases contact 34 into closed position. The speed at which contact 34 separates from contact 33 is varied by varying the tension in spring 39 which is controlled by a set screw 4| mounted on'a bracket 42 insulatingly supported by the disk 30.
The other circuit breaker 32 has contacts 43 and 44 corresponding, respectively, to contacts 33 and 34 of breaker 3|. The parts of the breaker 32 supporting contacts 33 and 34 have been identifled by reference numbers which are the same as the reference numbers applied to the corresponding parts of the breaker 3|, except that the letter a" is affixed.
The contacts of the circuit breakers 3| and 32 are connected with a commutating device located on the reverse side of the disk 30. The commutating device comprises an outer split ring including the parts K and L, a continuous collector ring N and a continuous collector ring U. The contacts 33 and 34 of breaker 3|, which will hereinafter be known as contacts 0, are connected with the split connector rings K and L by wires 53 and 54 respectively. The contacts 43 and 44 of breaker 30, which will hereinafter be known as contacts P, are connected by wires 63 and 64 respectively with continuous collector rings Q and N. The frame of the electric motor insulatingly supports brushes 13 and H which bear upon the half rings K and L, a brush 7". which bears on the ring N and a brush 13 which bears on the ring Q. The ring parts K, L, N and Q are insulatingly supported by the disk 30. The ends of the ring parts K and L are provided with tungsten inserts T.
The brush i0 is connected by wire 14 with wire 15 which is connected between brush 12 and motor commutator brush 22; brush 10 is also connected by wire 13 with a resistor I which is connected by wire 11 with line wire 23. A condenser H is in shunt with resistor 1. Brush 1| is connected by wire I3 with a contact D. Brush I3 is connected by wire 13 with a contact E. The contacts D and E are parts of a relay which include also a double which is insulatingly supported by 2 v contact mounted on an armature 80 pivoted at 8| and urgedin a clockwise direction by a spring 82, one end of which isflxed with armature 80 and the other'with a stationary part 83. The relay '5 1 includes an electromagnet B, the winding of which 5 cuit: wire 24,
5 the speed is regulated by the contacts 0. when segment L, brush II,
is connected to line wire 26 and the other end of which is connected through a condenser F to a line wire 24. It will be observed since magnet winding Bis connected only by capacity F with line wire 24 the relay will operate only on alternating-current applied tojthe; line wires 24 and 26.
When'direct current is applied to the wires 24 and 26 current flows motor field winding. 23, armature I5, wire 14 to the brush l0, brush II; wire 18,
come the bias of the spring 39, thereby causing 30 the contact 34 (of the pair of contacts 0) to be separated from the, contact 33. Since these contactsfO are in series with the electricmotor as previously explained, theoperation of the motor will be aiiected by the opening of the contacts 0,
35 whereby the motor speed will decrease; and then,
when the speed has decreased to a certain value the contactsO will close again. In this way the speed is regulated by the speed-responsive circuit breaker' 3|. The resistor I, which like the condenser H is in shunt to the contacts 0, is of a suitable value for preventing the motor circuit from being interrupted when the contacts are open, while not affecting the speed of regulation. The resistor I reduces sparking at the contacts 0 and is assisted by the condenser H in this function.
direct current operation of the motor the description has been given as though the commutating segments K and L were stationary. Obviously their position is reversed every half revolution of the motor shaft. Therefore, every half revolution thedirection of the currentnow through the contacts O is reversed. In this way the, transfer.
of material across the contacts in one direction is compensated for by practically equal transfer, of
the material between the contacts in the opposite a direction. Then the tendency for. the contacts to;
build up or pit is practically eliminated. v
When alternating current is applied to theline wires 24 and 26 current flows denser F and the relay armature is attracted toward the magnet and opens the circuit between C and'D and closes the circuit between-C and E. Therefore, the following circuit is operative during which alternating current is applied to the wire: line wire 24, motor fleld'winding 22, armature of the motor,
wire-15, brush l2, commutating ring N, wire 84,,
70 contacts P wire 48; commutatlns r1118 Q, brush 1;, 1.
ll, contact E, contact-C, armature l0 and will then be seen that, when wire line wire 24. It alternatin current 24 and 28, the continuous llector rings N and through the following cirlinewire "and Q must be used.
' speed governor weight 38 will over- In describing the circuits which function during through the con ding B. Hence, the
is applied to the line wires.
contacts P'are used. These contacts P function to regulate the motor speed when operating on alternating current in the same manner as the contacts 0 function to regulate the motor speed when operating on direct current. The condenser H and the resistor I are also shunted across the contacts P through the Q and the governor following circuit: wire 16, brush 10, wire 14, wire I5, brush 12, collector ring, N, wire 64, contacts P, wire 63, ring Q, brush 13, wire 19, contact E, contact C, armature 80, wire 26 and wire I1 back to the condenser H and resistor I. The condenser H and resistor I function to reduce sparking at the contacts E.
It has been found that, in order to obtain the desired operating life from the governor, the split collector rings K and L can not be used for alternating current operation on a volt circult and that the continuous collector rings N It is apparent from the foregoing description of the construction and mode of operation'of the governor circuits, embodied in the present invention, that there has been provided a motor with a in which very close speed regulation can be obtained and maintained over long periods of operation regardless of whether the motor is operated upon alternating or direct cur- I rent.
While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms-might be adopted, all coming within the scope of the claims which follow.
What is claimed is as follows:
1.- A control circuit for universal motors comprising, in combination, two speed responsive circuit breakers driven by the motor, means for automatically selectively connecting one or the other of said circuit breakers in circuit with the motor depending on whether the motor operates on direct current 01 on alternating current, whereby the motor speed will be regulated when the motor operates on either kind of current, and means for automatically reversing polarity through the contacts of that speed responsive circuit breaker which regulates the speed of the motor when operating on direct current.
2. A control circuit according to claim 1 in which the automatic selecting means comprises an electromagnet relay having an armature'normally biased tocomplete the circuit of the electric motor through the circuit breaker which controls motor speed for direct current operation and having an electro-magnet winding capacity-coupled across the line so as to be energized by alternating current only, the energizing of the electromagnet by alternating current causing the armature to disconnect the D. C. circuit breaker for controlling speed, and to connect the A. C. circuit breaker for controlling speed. 4 f N ,3. A control circuit according. to claim 1 in which the means for automatically reversing polarity through the contacts of the speed responsive circuit breaker which regulates motor speed when operating on direct current comprises a motor-driven bi-segmental, split collector ring having its segments connected respectively with said contacts and mounted, and brushes cooperating with the split ring for connecting the segments with the motor and line, the polarity through the segments being automatically reversed by the motor.
STANLEY H. SWARTHOUT.
US215426A 1938-06-23 1938-06-23 Universal motor speed governor Expired - Lifetime US2157640A (en)

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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2677798A (en) * 1950-10-09 1954-05-04 Bekey Andrew Electrical supply system for operating loads
US3398328A (en) * 1966-04-21 1968-08-20 Irving B Collins Electrical relay circuitry for magnetizing systems and the like
US3707634A (en) * 1971-03-31 1972-12-26 Sperry Rand Corp Apparatus for extending contact life of relays utilized for a.c. load switching

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2677798A (en) * 1950-10-09 1954-05-04 Bekey Andrew Electrical supply system for operating loads
US3398328A (en) * 1966-04-21 1968-08-20 Irving B Collins Electrical relay circuitry for magnetizing systems and the like
US3707634A (en) * 1971-03-31 1972-12-26 Sperry Rand Corp Apparatus for extending contact life of relays utilized for a.c. load switching

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