Circuit apparatus for enabling use of an a-c tachometer as the speed signal from a bi-directional d-c machine
US4091314A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 27, 1976 |
| Grant date | May 23, 1978 |
| Priority date | — |
| Expiry date | Sep 27, 1996 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S388/907
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Circuit apparatus for providing a signal indicative of speed and direction of rotation of a d-c machine is provided which utilizes an a-c tachometer output as the speed signal from the bi-directional d-c machine. The circuit apparatus includes means responsive to the armature terminal voltage and armature current to provide a signal proportional to the counter electromotive force generated in the armature. Polarity circuit means responsive to nulls in the armature current and the signal proportional to the counter electromotive force generates a signal which is a function of the polarity of the counter electromotive force. An absolute value circuit means is provided for receiving the output of an a-c tachometer driven by the d-c machine. The absolute value circuit means includes switch means responsive to the polarity signal for generating an output signal having an absolute value proportional to the output of the tachometer and the speed of the d-c machine and a polarity which is a function of the direction of rotation of the d-c machine.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.