Polyphase power factor controller
US4412167A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 30, 1981 |
| Grant date | Oct 25, 1983 |
| Priority date | — |
| Expiry date | Mar 30, 2001 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E40/30
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A power factor controller for an AC induction motor which includes a control circuit adapted to be electrically connected in series with the motor for controlling the voltage applied to the motor. A sensing circuit provides phase lag signals corresponding to the difference in phase between the current through the motor and voltage across the motor. An oscillation circuit produces a cyclical output whose frequency is variable and is dependent on the value of the phase lag signal. A counter receives the cyclical output and produces a control signal corresponding to a predetermined cycle count of the cyclical output so that the duration of the control signal is dependent upon the phase difference. The control signal is applied to the control device for controlling the conduction angle of the voltage applied to the motor to thereby provide power to the motor in accordance with motor loading. Additionally, both soft start and hard start circuits are included and current limit or current trip circuits are provided for starting and running of the motor. A polyphase power factor controller is described and an additional phase loss lockout protection circuit is included.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.