Multi-level disk drive motor speed control
US4477750A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 17, 1982 |
| Grant date | Oct 16, 1984 |
| Priority date | — |
| Expiry date | May 17, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P23/186
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A three level motor speed control for a device such as a magnetic disk drive requiring a closely regulated running speed provides for acceleration, deceleration, obtaining close speed regulation and maintaining speed regulation of a rotating device during operation. The first level control provides acceleration or deceleration while checking velocity each eighth revolution and the second level control uses single revolutions to measure speed over an accurate rotational distance to obtain close speed regulation. Both level one and level two are controlled by the device controller. During run conditions with no error signal, a third level of control of the closely regulated velocity is maintained by separate hardware circuits which frees the processor for other uses. An error condition forces control to level one for re-establishment of the regulated running speed and a command to stop the drive forces control to level one for deceleration and stop procedures.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.