Siemens 6EP1961-3BA21 SITOP PSE202U 24V/40A Redundancy Module

The Siemens 6EP1961-3BA21 is a SITOP PSE202U redundancy module that decouples two 24 V DC SITOP power supplies, each contributing up to 20 A, to a combined 40 A output. It signals status through relay contacts and front LEDs, reaches 96.6% efficiency, and mounts on a 35 mm DIN rail in an IP20 enclosure measuring 70 x 125 x 120 mm.

Technical Specifications

Certifications & Standards

• CE
• EAC
• ABS
• DNV

Selection Notes

This redundancy module accepts two independent 24 V DC feeds and isolates them from each other so a fault or maintenance shutdown on one supply does not pull down the other - pair it with two SITOP power supplies each sized to carry the full 40 A load alone for true N+1 redundancy, not two units each rated for half the load. The isolated relay contact reports loss of either input below the 20-25 V adjustable threshold, giving a hard-wired signal for a PLC or alarm panel independent of any fieldbus. At 96.6% efficiency and a 6.47 million hour MTBF at 40 °C, the module itself is not the weak point in a redundant supply chain.

Applications

Used to combine two SITOP 24 V DC power supplies into a redundant 40 A DC bus for PLC racks, remote I/O, and other loads where a single power-supply failure must not interrupt control power.