Electric motor control apparatus
US4322672A · kind A · utility
5Cited by
5References
8Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Nov 16, 1979 |
| Grant date | Mar 30, 1982 |
| Priority date | — |
| Expiry date | Nov 16, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P21/00
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
Electric motor control apparatus includes a variable-frequency oscillator 10, a counter 11 clocked by the oscillator, and signal generating means 12 arranged to generate two sinusoidal voltages in quadrature with one another. The two voltages are applied through separate amplifiers 22, 23 to separate stator windings 24, 26, of the motor, the stator windings being 90.degree. apart. Control means includes a bistable circuit 28 producing a signal lagging 45.degree. behind one sinusoidal voltage, and a phase sensitive detector 29 arranged to vary the frequency of the oscillator 10 to maintain a constant phase difference.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.