Siemens SITOP PSU300S Switch Mode DIN Rail Power Supply, 340 → 550V ac ac Input, 24V dc dc Output, 40A Output. This 3-phase switch mode power supply from Siemens’ SITOP range converts the incoming supply into the required voltage, frequency and current for your machinery. It packs an excellent overload response into compact dimensions of 150 (W) x 150 (D) x 145mm (H).