Importance

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Abstract

A switching system for powering first and second electrical loads from a voltage supply, the electrical loads being operable from controls and adapted to be connected to the voltage supply by the switching system. The switching system includes switching circuitry having a control element which is responsive to a control voltage difference to cause the switching circuitry to become conductive, the switching circuitry having a switch terminal connected to a first supply line and another switch terminal connected to the first electrical load. The switching system also includes additional circuitry responsive to the controls for generating the control voltage difference when the voltage supply is connected to the first supply line thereby powering the first electrical load from the first supply line. The switching system further includes further circuitry responsive to the controls for generating first and second control signals. Also included in the switching system is a contactor responsive to the second control signal for connecting the voltage supply to a second supply line, the second electrical load connected to the second supply line and another contactor responsive to the first control signal for connecting the second supply line to the first supply line thereby connecting the voltage supply to the first supply line and for disconnecting the second supply line from the first supply line to interrupt power through the switching circuitry thereby discontinuing the supply of power to the first electrical load. Other forms of the switching system and a testing system are also disclosed.

First Claim