Electric motor controller with bypass contactor
US4996469A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 16, 1990 |
| Grant date | Feb 26, 1991 |
| Priority date | — |
| Expiry date | Mar 16, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P27/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A three-phase motor controller includes a bidirectional thyristor switch to couple each phase of an electrical supply to a motor. The motor is started by rendering the thyristors conductive during successively greater portions of each cycle of AC electricity from the supply. In order to reduce the cooling requirements of the controller, a contactor is connected in parallel with the thyristors to provide apply electricity to the motor once it reaches full speed. When the controller receives a signal to stop the motor, the contactor is deactivated and the controller goes through a sequence to synchronize the thyristor triggering to the AC electricity. The synchronizing process provides a smooth transition from contractor control back to thyristor control of the application of electricity to the motor. Once thyristor control resumes, the controller executes a triggering routine which decreases the voltage applied to the motor and produces a braking effect.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.