Method of and device for contactless measurement of rotary speed of direct current motor by forming autocorrelation sequence
US5581178A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1994 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Mar 30, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01P3/80
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of and an arrangement for rotary speed determination in an electric motor is used to determine an instantaneous motor rotary speed from an alternating portion of the current caused by switching on and off of the commutator with a recognizable periodicity. An endless auto-correlation sequence is formed, and the rotary value is determined from the distance between the maxima or minima of the auto-correlation sequence. In combination with a further method for rotary speed determination from the alternating portion of the current with the use of twice fourier transformations, a very reliable and error-free rotary speed determination is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.