Fail-safe system for pulse-controlled three-terminal d.c. motor
US4406979A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 13, 1981 |
| Grant date | Sep 27, 1983 |
| Priority date | — |
| Expiry date | Mar 13, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P7/29
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A pulse control circuit for a d.c. series motor having an armature and two oppositely-wound field windings, comprises a contactor in series with the motor, two main thyristors each connected in series with the armature and a respective one of the field windings, means for controlling the mark-to-space ratio of conduction of each thyristor, one or other of the main thyristors being brought into operation in dependence upon the desired direction of drive of the armature, means for sensing failure of commutation of the main thyristor, and means for causing opening of the contactor in response to such sensing. The control circuit includes means for firing the other main thyristor immediately commutation failure is sensed, thereby to limit the net field flux and motor torque in the period during which the contactor is opening.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.