Electric current measurement apparatus for a solid state motor controller
US5153489A · kind A · utility
Inventors
Key dates
| Filing date | Jun 10, 1991 |
| Grant date | Oct 6, 1992 |
| Priority date | — |
| Expiry date | Jun 10, 2011 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P27/02
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electric induction motor is coupled to a source of alternating current by a thyristor switch. A control circuit triggers the thyristor switch to create conductive and non-conductive states during each cycle of the alternating current. A circuit senses the voltage across the thyristor switch during a non-conductive state. From that sensed voltage and known characteristics of the motor being controlled, the control circuit derives a measurement of the current flowing through the motor in the conductive state of the thyristor switch. One of two different derivation techniques is used depending upon the length of the non-conductive state. The control circuit includes a means for calibrating the derivation of the current measurement for a specific motor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.