Disc drive spindle motor with low cogging torque
US4858044A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 30, 1987 |
| Grant date | Aug 15, 1989 |
| Priority date | — |
| Expiry date | Oct 30, 2007 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/2009
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A disc drive spindle motor having a stator with nine evenly distributed windings separated by relatively large slot openings, further comprises a rotor having a radially polarized eight-pole magnet. The motor of this invention has three phases, the first phase starting at any winding end of the nine windings and incorporates the windings n, n+2 and n+4 connected in series and being wound in the same direction; the second phase starting at the winding n+3, and incorporating the windings n+5 and n+7 connected in series and being wound in the same direction; and the third phase beginning with the winding n+6 and incorporating the windings n+8 and n+1, connected in series and wound in the same direction. The starting points of the three phases are selected to provide the necessary 120.degree. phase shift between windings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.