Apparatus and method for soft-starting a three-phase motor
US5883486A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 20, 1998 |
| Grant date | Mar 16, 1999 |
| Priority date | — |
| Expiry date | Jan 20, 2018 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02P1/26
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An apparatus and method for soft-starting a three-phase motor for connection to a three-phase power source for driving a three-phase motor. Soft-start provides a way to reduce the amount of starting torque and current during starting conditions. First, second, and third conductors are connected between a three-phase power source and a three-phase motor. A power contactor interrupts and provides current along the three conductors. A phase-shifting element for shifting the phase of the power signal normally outputted from the first conductor to match the phase of the power signal normally outputted from the third conductor is connected between the first and third conductors. A switching apparatus having first and second switch elements is connected between the phase-shifting element and the third conductor. When the first switch element is closed, current flows from the first conductor to the motor via the phase-shifting element. When the second switch element is open, no current flows from the third conductor to the motor directly. In this mode, the motor is running on single-phase power. When the states of the first and second switch elements are flip-flopped, the motor runs on thr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.