The Siemens 6ES7407-0KR02-0AA0 is a PS407 power supply for the S7-400 rack, delivering 10 A at 5 V DC on the backplane bus and up to 1 A at 24 V DC. It accepts a wide range of inputs — 120/230 V AC or 120/230 V DC — making it a single SKU for plants with mixed line voltages.
Input ratings and hold-up
Rated input currents: 0.9 A at 120 V AC, 1 A at 120 V DC, 0.5 A at 230 V AC or DC. Inrush current peaks at 63 A for 1 ms half-width. On mains failure, the unit holds up the output for 20 ms minimum; it also supports mains buffering per NAMUR recommendation.
Wiring and battery backup
Connection uses 3 × 1.5 mm² solid or stranded wire with end sleeve, accepting external diameter 3 mm to 9 mm. An optional backup battery (1× lithium AA, 3.6 V / 2.2 Ah) maintains the backplane buffer when mains is off. Short-circuit protection is built in. Leakage current is max. 3.5 mA.