Circuit for operating a synchronous motor from a dc supply
US4431953A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1981 |
| Grant date | Feb 14, 1984 |
| Priority date | — |
| Expiry date | Aug 31, 2001 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/21
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Commutation of the stator windings of a synchronous motor energized by a d.c. supply is controlled by comparison of voltages induced in two stator windings neither of which is a winding previously energized nor a winding about be energized. For speed control, turning on of the winding next energized can be delayed controllably. Motor current during start-up or overload can be limited by chopping, with a variable keying ratio, the d.c. supply connection to the motor during the first 80% of the period of energization of each stator winding. For reducing delay in starting, the rotor may be brought into a particular position automatically every time the motor is stopped or, in the case of a fuel pump motor for an injection type internal combustion engine, just before starting the engine through a supplementary contact controlled by the ignition key. Starting up can be provided by two initial pulses of commutation provided by means of an oscillator and two transistors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.