High torque reduced starting current electric motor
US6246141A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 23, 1999 |
| Grant date | Jun 12, 2001 |
| Priority date | — |
| Expiry date | Apr 23, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K17/20
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An AC squirrel cage motor runs with a rotor current frequency equal to the slip of the motor times its excitation frequency. It is desirable to reduce the rotor current on start up by means of an increased resistance, and then to run the motor with a reduced resistance once it is started. This invention takes advantage of the skin effect of high frequency currents by increasing rotor end ring resistance during startup. After the motor has started up, and has reached full speed, the rotor frequency is reduced to merely the slip multiplied by the stator frequency. The skin effect on the rotor current is less, and the motor runs with reduced resistance.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.