Tachometer check apparatus
US4575664A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 12, 1984 |
| Grant date | Mar 11, 1986 |
| Priority date | — |
| Expiry date | Mar 12, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/921
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electronic motor control system is taught herein which utilizes a tachometer check circuit. The tachometer check circuit is an electrical circuit which is interconnected with the output terminals of the tachometer. The circuit is utilized when the tachometer is at standstill to determine if the tachometer is functional, that is, is it internally correctly wired to produce an expected signal upon rotation. If such is the case, then motor start-up may take place. A second test is performed after motor start-up for determining if an appropriate amount of output voltage is being produced by the tachometer during the start-up phase. This is based on expected values of voltage during a short period of time after start-up. If such is not the case, the motor control system is disabled and the motor is stopped. The system is utilized for embodiments which include AC tachometers as well as DC tachometers used on unidirectional or bidirectional rotational systems.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.