Brushless d-c motor system
US4099104A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 17, 1977 |
| Grant date | Jul 4, 1978 |
| Priority date | — |
| Expiry date | Mar 17, 1997 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K29/08
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
To improve low noise operation of a brushless permanent magnet d-c motor, and reduce voltage peaks and stresses on switching transistors connected in series with stator windings thereof, a galvanomagnetic sensing element, such as a Hall generator, is located on the stator positioned in the gap between adjacent poles and subjected to stray leakage flux from the stator poles in such a way -- for example by means of soft-iron flux guide elements -- that the leakage field from the stator pole which is oppositely poled -- at any instant of operation -- to the rotor pole which controls operation of the galvanomagnetic sensing element provides a counter-acting flux to the galvanomagnetic sensing element, thus flattening the turn-off flanks of control pulses controlling current flow through the stator winding.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.