Method of and system for minimizing current consumption of one or more A-C motors driving a variable load
US4477761A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 8, 1982 |
| Grant date | Oct 16, 1984 |
| Priority date | — |
| Expiry date | Dec 8, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P2207/05
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
In order to minimize the current consumption of an alternating-current motor of the induction or the synchronous type (or possibly a plurality of such motors connected in parallel) driving a variable load, a sensor coupled to a supply line of the motor detects the occurrence of a significant change in its operating current and determines the sense of that change. A controller responsive to signals from the sensor then reduces the supply voltage by an incremental or decremental step and, if the sensor detects a resulting decrease in amperage, continues with one or more similar steps until the current levels off. If the initial voltage modification causes the current to rise, the controller progressively changes the supply voltage in the opposite sense until the amperage reaches a minimum. In the case of an induction motor whose rotor speed is controllable by variations in slip frequency with the aid of an arithmetic unit responsive to a tachometric signal and to voltage feedback from the input of its stator, the desired current reduction is achieved by an incrementation or decrementation of the feedback voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.