An AC supply voltage must be provided to the ZV continuously. While the ZV will drop-out and pick-up based on an adjustable millivolt set point, the signal circuit will accept up to 600VAC. With no voltage on the signal terminals, the internal relay is energized, transferring the output contacts. When the voltage exceeds the set point, the relay will de-energize. When used on Zero Speed applications, a loss of input voltage will cause the relay to remain de-energized as if the motor were still running. Reverse operation is available. For DC current sensing, select a 100mVolt shunt of the correct current rating and connect the shunt in series with the load and in parallel with the ZV’s signal terminals.