Self-contained hydraulic switch operator

A self-contained power operator powered from an external alternating current electrical power source for opening and closing an electric power line switch, comprising a reversible hydraulic rotary actuator, means for mechanically connecting said actuator to the line switch to produce rotary directional movements of the line switch corresponding to rotary directional movements of the actuator, a reversible hydraulic pump having separate outlet ports, separate means hydraulically connecting said outlet ports to opposite sides of said actuator, each of said hydraulic connecting means comprising a single conduit connected at its opposite ends to one of said pump outlet ports and to the corresponding side of said actuator, a reversible direct current electric motor drivingly coupled to said pump for driving the same selectively in opposite directions to produce respectively switch opening and closing directional rotary movements of said actuator, permanent means for electrical connection to an external alternating current electrical power source, an electric storage battery, a battery charger including a rectifier fed by said external alternating current power source connection means and permanently connected to said storage battery to maintain the same in charged condition, separate normally open power circuits connecting said storage battery to opposite poles of said motor for respectively energizing said motor for rotation in opposite directions, separate control circuits for selectively closing said power circuits to cause said motor to rotate in opposite directions, means for selectively energizing the respective control circuit, each said control circuit consisting solely of a limit switch and a relay coil in series, the limit switch in one of said control circuits being closed responsive to full closure of the line switch and opened when the line switch is open, the limit switch in the other of said control circuits being opened responsive to fully closure of the line switch and closed when the line switch is open, each said power circuit having a normally open switch consisting of a contactor of the relay coil in the corresponding control circuit closeable by energization of the latter whereby to energize the motor in the selected direction, a holding circuit connecting each said power circuit to the corresponding control circuit to maintain the latter energized throughout the full respective opening or closing movement of the line switch, said holding circuit including a normally closed switch consisting of a contactor of the relay coil in the opposite control circuit and openable when the opposite control circuit is energized to open said holding circuit switch and prevent energization of the corresponding control circuit and initiation of movements of the line switch in either direction during energization of the opposite control circuit and movements of the line switch in the other direction, each control circuit having a terminal intermediate the connection to the control circuit of the corresponding hold circuit and the limit switch in the control circuit for conductive attachment of remote control equipment, whereby to permit initial energization of the respective control circuits from remote locations, both said control circuits having a ground line with a normally closed switch therein, a time delay relay coil energizable by said control circuits and having a contactor forming the normally closed switch in said ground line, said time delay relay coil being constructed and arranged to open its contactor a predetermined short interval after its energization from either of said hold circuits, whereby to open said control circuits if the respective opening or closing operation of the line switch is not completed at the expiration of such time interval and thereby prevent damage to the operator if the line switch is inoperable for any reason.