Load sensing, soft-braking method and apparatus using the same
US5457372A · kind A · utility
Inventors
Key dates
| Filing date | Jul 16, 1993 |
| Grant date | Oct 10, 1995 |
| Priority date | — |
| Expiry date | Jul 16, 2013 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB66B1/308
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A device for precisely stopping an induction motor includes a current transformer for sampling a power level of an alternating current power source driving the motor during run time and an AC-DC converter/sample-and-hold circuit for generating a sampling voltage signal according to the sampling. Also included is circuitry responsive to the sampling voltage signal for determining an amount of direct current necessary to induce a static magnetic field to produce a torque within a stator winding of the motor sufficient to precisely stop the motor. A silicon controlled rectifier generates the determined amount of direct current and control circuitry causes the generated current to be injected into the stator winding. The induced static magnetic field static magnetic field is sufficient to precisely stop the motor regardless of the size of the load the motor is driving because it follows the sampling voltage signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.