Reliance Automax 57C494. In stock ships today. 57C494. 57C494A. 57C494B. Power Supply module. The Power Supply module is a circuit assembly enclosed in a protective aluminum housing with integral heatsink. The module plugs into the leftmost position of the Automax Multibus rack and provides, through the Multibus backplane, all of the voltages necessary to power the logic circuitry of all card modules in the rack. The power Supply module is the electrical interface between the 120V ac input power and the Automax system. The AC line filter located in the Multibus rack is connected between in incoming power and the Power Supply module. No other connections to the AC line are made between the line filter and the Power Supply module. On power-up, a soft-start feature gradually increases the output until five milliseconds after the voltage exceeds the volts necessary for logic operations. At this time, an initialize signal is generated and the P/S READY indicator is illuminated. The holdover time on loss of AC input is 20 milliseconds. Three milliseconds before loss of the regulated DC power, a Multibus power fail interrupt signal is generated for orderly system shutdown.