Wound rotor motor control
US4721898A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 17, 1986 |
| Grant date | Jan 26, 1988 |
| Priority date | — |
| Expiry date | Nov 17, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P25/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A control for a wound rotor induction motor including shorting switches in a secondary resistance network comprises an input comparator with voltage limiting switched by the rotor voltage, a pulse generator responsive to the input comparator to generate voltage pulses of predetermined constant duration at a frequency proportional to the frequency of the rectangular voltage wave, a low pass filter effective to filter the output of the pulse generator to a DC voltage inversely related to rotor speed, a DC power supply effective to generate a plurality of DC reference voltages, a plurality of switch control comparators, each receiving the output of the low pass filter on one input and one of the DC reference voltages on the other input and a plurality of switch actuators, each switch actuator being responsive to the output of one of the switch control comparators to activate a group of shorting switches at a predetermined rotor speed during motor acceleration and deceleration. An attenuated signal at the line frequency is substituted, when there is no stator voltage, at the input comparator inputs in the absence of rotor voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.