| 摘要 |
A motor controller providing a disconnect and a single set of movable contacts, to provide operation and protection of a motor and associated circuitry over a complete range of possible currents. Plug-in modules for a circuit disconnect, a solid state overload relay, and an instantaneous trip unit are provided. The disclosed integral modular motor controller consists of five major components: (1) an isolator switch, (2) arc chambers, (3) a linear slot motor drive, (4) a drive operator, and (5) a solid state control. For a normal motor starting operation and for fault currents up to a predetermined value, such as 1200 amperes, an electromagnetic actuator is used to open the contacts a relatively small distance such as 0.25 inch. For higher fault currents a drive or linear slot motor opens the contacts to a greater separation such as 1 inch. The disclosed modular integral motor controller utilizes a disconnecting switch connected in series with a movable bridging contact arm on which arm mounted a pair of spaced apart movable contacts aligned to engage a pair of stationary contacts when the motor controller is in the closed position to complete an electric circuit to the controlled motor. The bridging contact arm is provided with two open positions; one for use in motor control and relatively low fault currents, wherein relatively small contact separation is involved, and a second open position used during high fault currents and current limiting situations, wherein the movable contacts are separated from the stationary contacts by a relatively large separation. |
