Turntable drive system for video disc player
US4239237A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | May 29, 1979 |
| Grant date | Dec 16, 1980 |
| Priority date | — |
| Expiry date | May 29, 1999 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K17/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A turntable drive motor comprises a stator having a core defining an airgap for receiving a rotor, and a field winding for establishing an alternating magnetic flux of a given frequency therein. An elastic belt is disposed about a pully mounted on the rotor shaft and a flange secured to the turntable. A ring having a plurality of permanently magnetized poles of alternate polarity along its periphery is attached to the flange. A pair of elements are secured to the core for diverting a portion of the stator magnetic flux to a region adjacent to the ringed magnets. The relationship between the excitation frequency and the number of the permanently magnetized poles is such that deviations in the rate of rotation of the turntable for a desired rotational rate are opposed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.