Brushless DC motors
US4158795A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 26, 1977 |
| Grant date | Jun 19, 1979 |
| Priority date | — |
| Expiry date | Oct 26, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P6/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A brushless DC motor capable of change of rotational direction is disclosed. The feed of a high-frequency voltage signal to switching elements is sequentially changed to orderly excite stator windings by the outputs from rotor angular position detectors so that the rotor is rotated in a desired direction. Another high-frequency voltage signal is applied to the switching elements at a time when opposite direction rotation is required, so that the high-frequency voltage signal applied to one of the switching elements in response to the outputs of the detectors is cancelled by the other high-frequency voltage signal. Therefore, the order of the excitation of stator windings is inverted and, thus, the rotor is rotated in the opposite direction. The other high-frequency voltage signal has the same frequency as, a greater amplitude than, and a phase difference of 90.degree.-270.degree. from, the high-frequency voltage signal which is applied to one of the switching elements in response to the control of the detectors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.