Synchronous motor torque control device
US4931715A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 16, 1988 |
| Grant date | Jun 5, 1990 |
| Priority date | — |
| Expiry date | Feb 16, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P25/024
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method is described for controlling synchronous motor torque, utilizing a three-phase switch connected in a circuit to the input of a polyphase synchronous motor, and a switch control circuit. The switch control circuit senses the AC voltages input to the synchronous motor and produces signals that open and close the three-phase switch in phase with the input motor voltage, producing positive motor torque during normal operation. If input AC power is lost, the switch control circuit acts to prevent a reverse flow of high current from the motor from entering the power source bus. When input power, after a short time, returns, the switch control circuit acts to close the three-phase switch in such a manner as to permit only real power applied to the synchronous motor and thus positive torque that accelerates the motor speed and quickly restores the motor to synchronism with the input power source.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.