Product Introduction
When system uptime is critical, the Siemens 6EP1961-3BA21 SITOP PSE202U redundancy module ensures reliable decoupling of two power supplies. This industrial automation module delivers up to 40A total output with an impressive 96.6% efficiency, reducing energy waste and operational costs. Designed for DC 24V networks, it provides a controlled, isolated output and a relay alarm contact for monitoring input voltage thresholds.
Technical Specifications Breakdown
The Siemens 6EP1961-3BA21 is built for demanding 24V DC applications. Below are the key parameters from the official datasheet:
| Parameter |
Value |
| Input voltage (DC) |
24 … 24 V |
| Input voltage range (DC) |
24 … 28.8 V |
| Rated output voltage |
24 V DC |
| Rated output current |
40 A |
| Max. aggregate current |
40 A |
| Efficiency |
96.6 % |
| Power loss at rated load (typical) |
34 W |
| Power loss no-load (max.) |
1.5 W |
| MTBF at 40 °C |
6 471 654 h |
| Galvanic isolation |
SELV per EN 60950-1 (relay contact) |
| Protection class |
III / IP20 |
| Weight |
0.5 kg |
| Dimensions (W×H×D) |
70 × 125 × 120 mm |
These specifications ensure the Siemens 6EP1961-3BA21 operates reliably in industrial environments with natural convection cooling from -25 °C to +60 °C.
Industry Applications
The Siemens 6EP1961-3BA21 is ideal for critical control cabinets where uninterrupted power is mandatory. Common use cases include:
- Decoupling two 20 A SITOP power supplies to create a redundant 40 A supply for PLC and DCS racks.
- Powering safety-instrumented systems where a single supply failure could cause costly shutdowns.
- Supplying 24 V DC to motor drives, sensors, and actuators in manufacturing lines.
With its 96.6% efficiency, this module minimizes heat generation and energy costs over the product lifetime, aligning with ROI-focused maintenance strategies.
Installation & Setup Guidance
The Siemens 6EP1961-3BA21 mounts swiftly onto a DIN rail EN 60715 35×7.5/15. Use the provided screw terminals for input, output, and ground connections (0.33…10 mm² wire). Ensure top and bottom clearance of 50 mm each for adequate airflow. No side spacing is required. The relay alarm contact uses three additional screw terminals (0.5…2.5 mm²). No wall or S7 rail mounting is supported.
Selection Guide & Purchasing Advice
Before ordering, confirm your system voltage is 24 V DC and that each power supply output does not exceed 20 A. The Siemens 6EP1961-3BA21 supports up to 40 A total, with derating of 3%/K above 60 °C. As a trusted supplier, PLC Source PRO (via ubest101) stocks this exact model—ensuring genuine Siemens quality and fast delivery for your critical spares.