Apparatus for controlling the speed and direction of rotation of a DC motor
US4258299A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 1979 |
| Grant date | Mar 24, 1981 |
| Priority date | — |
| Expiry date | Jan 26, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B19/28
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A single pickup head generates an alternating signal proportional to the rotational speed of a DC motor which can be rotated in either of two directions, and such alternating signal is employed by speed and/or phase control circuits to control the motor speed relative to a reference speed in a selected one of the two directions. An overspeed sensing circuit detects speed runaway, which can occur when the motor is rapidly rotated in the direction opposite to the selected direction, and the overspeed sensing circuit then interrupts the motor drive voltage until the motor speed decreases to below its normal speed. At and below normal speed in the undesired direction, the normal torque acts in the selected direction to rapidly reverse the direction and to accelerate the motor to normal speed in the selected direction.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.