Brushless direct current motor and control therefor
US4355255A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1979 |
| Grant date | Oct 19, 1982 |
| Priority date | — |
| Expiry date | Aug 28, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K29/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A brushless direct current motor is provided with a rotor having a rare earth magnet within a nonferrous cylinder and a pair of coil windings which are air wound. To effect rotation of the rotor, current through the coils is controlled to rotate the resultant magnetic flux generated by the currents through the coils so that the rotor attempts to align itself magnetically with the resultant flux from the coils. Both coils are simultaneously energized and the polarity of current flow through the coils is reversed in such a manner that there is a current reversal through only one of the coils whenever the current is switched. Coil switching is directed by a triggering magnet fixed on the rotor shaft, which magnet operates Hall effect switches. The Hall effect switches in turn operate power switches to apply the correct voltage and polarity simultaneously to both windings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.