Switch operating mechanisms for high voltage switches

Abstract

A three-phase, high voltage switch arrangement is operated through a connected drive shaft by a switch operating mechanism that can be either driven by motor power or manually operated. When manual operation is desired, a crank handle is folded out of a stored position to an operating position. An improved mechanism is provided to prevent the crank handle from operably engaging the switch operating mechanism until stored torsional energy (i.e., the potential energy due to torsional strain) in the drive shaft has been released thereby avoiding improper operation, such as unexpected whipping of the handle. In addition, when the crank handle is folded out to its operating position, the motor is disabled so that the motor can not be operated while the handle is engaged with the mechanism so that the handle cannot be driven by the motor. When it is desired to disconnect the switch operating mechanism from the switch so that maintenance and testing can be performed, a selector handle may be operated that disconnects the drive shaft from the operating mechanism and locks the drive shaft so that the switch cannot be accidentally opened or closed due to wind or vibrational forces. Also, while the selector handle is being operated, the motor cannot be operated while the drive shaft is being disconnected and locked.