Triac drive for three-phase line-powered linear induction motor elevator door operator
US5808246A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 25, 1995 |
| Grant date | Sep 15, 1998 |
| Priority date | — |
| Expiry date | Sep 25, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02K41/025
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
An electronic motor drive produces a required motion profile for an elevator door operator actuated by a three-phase, line-powered linear induction motor (LIM) by means of an array of TRIAC switches producing selected forces from the LIM. The TRIAC drive is capable of producing acceleration, deceleration or free coast in either the open or close direction of door operation. When controlled by an algorithm such as a "time-optimal switch point" or "bang-bang" control, the TRIAC drive produces the required motions from the linear induction motor for elevator door operation. The motor windings may be switchable between delta and wye hookups to provide two distinct thrust levels. Phase angle modulation may be used to provide finer control of thrust. The linear motor may be a 12-slot arrangement having four poles and three phases and arranged with flux emanating from the stationary primary (on the car) to a stationary backiron part of the secondary also mounted on the car, wherein the flux passes through a movable copper part of the secondary attached to the elevator door and passing between the primary and the backiron.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.