US3753060A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Induction motor system for traction
Assignee: Lear Motors Corp
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Filing: 1972-06-05
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Granted: 1973-08-14
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Expires: 1992-06-05
Abstract
Abstract An electric induction motor/control system that provides the desirable high starting torque and torque-speed characteristic of series type direct current motors. The stator of the induction motor is polyphase with two specially interrelated winding sets per phase. The motor windings are supplied with unidirectional current pulses from silicon controlled rectifiers that are programmed to provide the traction mode of operation for the induction motor. The unique relation and interaction between the motor windings hereof and the associated electronic circuitry results in high power factor, good efficiency, and self-clearing SCR commutation action. The preferred motors use a squirrel cage rotor with no commutator, brushes, or slip rings. The complementary stator winding arrangements are not voltage limited, and thereby permit the construction of large power motor systems. Practical motor ratings are from fractional to over 500 horsepower, at speeds ranging from 600 to 40,000 rpm, and higher. The electronic control sections for even the high horsepower motors are operated at low voltage and with few watts. Control circuitry is provided that can operate the motor system with traction output characteristics similar to that of series motors; and with direct speed reversal in such mode. The motor system requires little maintenance, and may be hermetically sealed.
Inventors
- 👤 J Greenwell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 07:24
CPC Classifications
H; H02; H02K; H02K29/00; H02K29/03; H02P; H02P23/00; H02P23/28
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
122 words
A polyphase motor system comprising a stator and an induction rotor, said stator containing a plurality of half-phase windings in paired consequent pole array with one pair for each effective phase for the motor in polyphase operation, a controlled rectifier for each of said half-phase windings, control means connected with said controlled rectifiers to selectively establish conduction periods therefor and thereby for their associated half-phase windings to provide a rotating magnetic field in the stator for corresponding operation of said induction rotor, and a generator responsive to the rotational speed of said rotor to provide a dc signal corresponding in magnitude to said speed, said dc signal being coupled to said control means whereby said rotor is operated in the traction mode.
Claim 2
Dependent Claim
122 words
A polyphase motor system comprising a stator and an induction rotor, said stator containing a plurality of half-phase windings in paired consequent pole array with one pair for each effective phase for the motor in polyphase operation, a controlled rectifier for each of said half-phase windings, control means connected with said controlled rectifiers to selectively establish conduction periods therefor and thereby for their associated half-phase windings to provide a rotating magnetic field in the stator for corresponding operation of said induction rotor, and a generator responsive to the rotational speed of said rotor to provide a dc signal corresponding in magnitude to said speed, said dc signal being coupled to said control means whereby said rotor is operated in the traction mode.
Claim 3
Dependent Claim
50 words
A polyphase motor system as claimed in claim 1, in which said half-phase windings are arrayed about the stator with equal magnetic and physical separation between adjacent windings, associated windings of each pair beinG respectively interconnected into two symmetrical polyphase winding groups that are 180* apart magnetically in the stator.
Claim 4
Dependent Claim
38 words
A polyphase motor system as claimed in claim 1, in which said control means establishes the said conduction periods at respective 180* electrical separation between related half-phase pairs and thereby provide said rotating magnetic field in the stator.
Claim 5
Dependent Claim
44 words
A polyphase motor system as claimed in claim 2, in which said control means establishes the said controlled rectifier conduction periods at respective 180* electrical separation between related half-phase pairs in said winding groups and thereby provide said rotating magnetic field in the stator.
Claim 6
Dependent Claim
54 words
A polyphase motor system as claimed in claim 2, in which said half-phase windings are arrayed in the stator with relatively low mutual magnetic induction between the windings of respective pairs, whereby magnetic interaction among said stator windings cyclically effects self-clearing of the controlled rectifier conductions should any extend beyond its predetermined conduction period.
Claim 7
Dependent Claim
81 words
A polyphase motor system as claimed in claim 1, in which said control means includes a timing circuit that effects said successive conduction periods in equally spaced time intervals among said half-phase windings once during each cycle of applied motor frequency, said timing circuit having an electronic clock, and circuit means coupled to said clock and arranged to control its frequency and thereby the duration of said conduction periods to effect the said traction mode of operation of the induction rotor.
Claim 8
Dependent Claim
81 words
A polyphase motor system as claimed in claim 2, in which said control means includes a timing circuit that effects said successive conduction periods in equally spaced time intervals among said half-phase windings once during eacy cycle of applied motor frequency, said timing circuit having an electronic clock, and circuit means coupled to said clock and arranged to control its frequency and thereby the duration of said conduction periods to effect the said traction mode of operation of the induction rotor.
Claim 9
Dependent Claim
48 words
A polyphase motor system as claimed in claim 6, further including terminal means for connecting said half-phase windings to a source of dc operating voltage, said circuit means being arranged to vary the frequency of said clock and effect the said traction mode of operation of the rotor.
Claim 10
Dependent Claim
58 words
A polyphase motor system as claimed in claim 6, further including a generator responsive to the rotational speed of said rotor to provide a dc signal corresponding in magnitude to said speed, said dc signal being coupled to said circuit means to correspondingly change the frequency of said clock, whereby said rotor is operated in the traction mode.
Claim 11
Dependent Claim
58 words
A polyphase motor system as claimed in claim 7, further including a generator responsive to the rotational speed of said rotor to provide a dc signal corresponding in magnitude to said speed, said dc signal being coupled to said circuit means to correspondingly change the frequency of said clock, whereby said rotor is operated in the traction mode.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-08-13 | 1977-02-12 | 1977-08-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-13 | 1981-02-12 | 1981-08-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-13 | 1985-02-12 | 1985-08-14 | $7700.00 | Window Closed / Lapsed |