Variable-speed drive for single-phase motors
US6121749A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 10, 1999 |
| Grant date | Sep 19, 2000 |
| Priority date | — |
| Expiry date | May 10, 2019 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P27/047
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A single-phase variable-frequency power supply with two output voltages drives a single-phase AC motor that has a start circuit and main winding. For permanent split-capacitor motors, the power supply maintains a constant voltage to the start winding while it reduces the voltage to the main winding at lower frequencies. The power supply can similarly control the speed of capacitor-start and split-phase motors. For fans and pumps and other variable-torque applications, the power supply maintains approximately a constant ratio of main-winding voltage to the square of frequency. The power supply is preferably an electronic pulse-width modulated inverter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.