Method and apparatus for heating electrical motors and like devices
US4135122A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 25, 1977 |
| Grant date | Jan 16, 1979 |
| Priority date | — |
| Expiry date | May 25, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02E10/72
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A motor heat control circuit is provided for heating an electrical motor during the time of motor shutdown, with the circuit functioning to interconnect a winding of the motor with a source of alternating current voltage for substantially an entire half-cycle of the alternating current voltage but only at intervals comprising a selected plurality of cycles of the alternating current voltage. In its preferred form, the motor heat control circuit is adapted to be connected in shunt circuit with a main motor contactor normally interconnecting the motor winding with the source of alternating current voltage, and includes a controllable semi-conductor switch controlled by digital counting logic which is responsive to clock pulses developed from the alternating current voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.