US3617838A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Arrangement for stepless speed regulation of a motor fed with current from a converter
Assignee: BBC Brown Boveri AG Germany
•
Filing: 1970-01-23
•
Granted: 1971-11-02
•
Expires: 1990-01-23
Abstract
Abstract A converter motor which provides a stepless variable speed control includes a pair of stator elements surrounding a common rotor which may be of the squirrel cage type. Each stator of the motor is provided with at least two open three-phase winding systems supplied from a three-phase mains and which are connected periodically with cyclically interchanged phase sequence by way of a controllable valve group to form a star point. The individual valve groups are controlled periodically with a frequency f2 which is different from the mains frequency f1 supplying the three-phase windings so that the star points of the three-phase stator winding systems are periodically closed and opened to thus establish a rotary stator field which rotates with a frequency equal to f2- f1 and which reacts with the rotor to drive the rotor at the rotational frequency of the stator field.
Inventors
- 👤 Armand Brandt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 02:38
CPC Classifications
H; H02; H02P; H02P27/00; H02P27/04; H02P27/06
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
197 words
A converter motor providing a stepless type of speed control which comprises a rotor, a pair of stators surrounding said rotor, each said stator including thereon a group of three-phase windings, said three-phase windings of each group having one end of each phase winding thereof connected with a corresponding phase of a three-phase network supplying alternating current at a frequency f1, the other end of each said phase winding being connected to a corresponding point intermediate the diodes of a three-phase diode bridge, each said bridge being provided with a controllable semiconductor valve which when in a conductive state serves to short circuit the bridge and form a star point connection for the said other ends of said phase windings thereby to establish an energization circuit for the appertaining threephase winding and means reNdering the controllable semiconductor valves for the diode bridges correlated to the three-phase windings of the two groups periodically conductive and nonconductive and in succession at a frequency f2 thereby to establish on said stators a combined rotary field which revolves at a speed equal to the difference between the frequencies f1 and f2 and which thereby determines the running speed of the rotor.
Claim 2
Dependent Claim
197 words
A converter motor providing a stepless type of speed control which comprises a rotor, a pair of stators surrounding said rotor, each said stator including thereon a group of three-phase windings, said three-phase windings of each group having one end of each phase winding thereof connected with a corresponding phase of a three-phase network supplying alternating current at a frequency f1, the other end of each said phase winding being connected to a corresponding point intermediate the diodes of a three-phase diode bridge, each said bridge being provided with a controllable semiconductor valve which when in a conductive state serves to short circuit the bridge and form a star point connection for the said other ends of said phase windings thereby to establish an energization circuit for the appertaining threephase winding and means reNdering the controllable semiconductor valves for the diode bridges correlated to the three-phase windings of the two groups periodically conductive and nonconductive and in succession at a frequency f2 thereby to establish on said stators a combined rotary field which revolves at a speed equal to the difference between the frequencies f1 and f2 and which thereby determines the running speed of the rotor.
Claim 3
Dependent Claim
17 words
A converter motor as defined in claim 1 wherein said rotor is of the squirrel cage type.
Claim 4
Dependent Claim
48 words
A converter motor as defined in claim 1 wherein the controllable semiconductor valves correlated to the three-phase windings of each group are provided with quenching means by which each valve when rendered conductive in succession functions to quench the valve which had previously been in its conductive state.
Claim 5
Dependent Claim
75 words
A converter motor as defined in claim 3 wherein said quenching means for said controllable semiconductor valves of each group includes a commutation transformer provided with inductively coupled windings individual to and connected with each of the controllable valves, a quenching condenser included in the connections between each said transformer winding and the controllable valve correlated therewith, and a blocking choke connected in the circuit between the controllable valve and the diode bridge correlated therewith.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |