Reliance Automax. In stock ships today. 45C321. 475321. PLC. Power Supply Module. The power supply is a single plug-in circuit board, enclosed in a plated steel and black anodized aluminum (heatsink) housing. This unit provides all of the voltages necessary to power the logic circuitry contained on the cards that may be inserted into the card rack. In addition, voltages are provided to power the module logic circuitry in any directly connected rails. A terminal strip is included on the card faceplate for ease of input power wiring. Power supply features overvoltage protection. Overcurrent protection. Power up/down sequencing logic to ensure proper controller operation. LED Status Indicators. Three-position keyswitch. Terminal strip. Fuse. 45C321 has 20 amps. 120/240V 50/60 Hz. 2 card slots.