Motor direction contactor switching control
US5239242A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 30, 1991 |
| Grant date | Aug 24, 1993 |
| Priority date | — |
| Expiry date | Aug 30, 2011 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY02T10/70
- WIPO fieldTransport
- WIPO sectorMechanical engineering
Abstract
Motor control systems having direction contacts for steering current through a motor are commonly associated with electrical industrial vehicles, such as lift trucks. Advantageously, the operation of the direction contacts should be optimized in order to prevent switching the contacts when current is present to the extent that such switching can be eliminated. The instant apparatus includes a logic device for receiving speed and direction demand signals and responsively controlling the direction contacts associated with a vehicle motor. The logic device also receives signals from a current sensor responsive to the magnitude of electrical current flowing through the electric motor. In response to the motor current signal indicating a value less than a predetermined value concurrent with either the motor direction demand signal having a neutral value or the motor speed demand signal having a zero value, the logic means produces a neutral motor direction command signal. Therefore, optimal control of the motor direction contacts is attained.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.