The Siemens 6ES5955-5NB11 is a high-performance power supply unit engineered for the Siemens Simatic S5-135 and S5-155 controller families. This module provides critical power conversion for the 186U configuration, transforming input power into stable 24 VDC and 5 VDC outputs with a total capacity of 15 A. Designed for mission-critical industrial environments such as chemical processing, heavy metallurgy, and automated manufacturing, this unit ensures stable voltage regulation under fluctuating load conditions. By maintaining precise power delivery to the CPU and I/O racks, the 6ES5955-5NB11 minimizes electrical noise and prevents system resets, serving as a vital link in reducing unplanned downtime in legacy automation infrastructures.
Features
Designed specifically for Simatic S5-135 and S5-155 controller systems.
Provides dual voltage rails: 24 VDC and 5 VDC.
High-efficiency switched-mode power architecture.
Total current capacity of 15 A to support expanded I/O and CPU racks.
Heavy-duty industrial housing for enhanced electromagnetic interference (EMI) protection.
Optimized for rack-mounting in standard Siemens cabinets.
Applications
This power supply is intended for use in legacy Simatic S5 automation environments, including large-scale process control, heavy industrial manufacturing, and metallurgical plants where high-density rack configurations require reliable, isolated DC power distribution.
Technical Specifications
Model
6ES5955-5NB11
Brand
Siemens Simatic S5
Output Voltage
24 VDC / 5 VDC
Total Current Capacity
15 A
Operating Temperature
0 degC to 60 degC
Enclosure Type
Industrial Rack-Mount
Installation Guidelines
Ensure the system power is completely disconnected before installing or removing the power supply module.
Verify that the backplane is clear of debris and that the module is correctly seated in the designated rack slot.
Ensure adequate ventilation around the unit to maintain operating temperatures within the 0 degC to 60 degC range.
Use appropriate shielded cabling for all I/O connections to minimize electrical noise.
Check for proper grounding of the rack assembly to prevent ground loops and ensure stable voltage regulation.
Strictly adhere to backplane power distribution standards to avoid voltage drops during peak demand cycles.
FAQ
Is this power supply compatible with all S5 series?
The 6ES5955-5NB11 is specifically engineered for the Simatic S5-135 and S5-155 controller families. Please verify your specific rack configuration and power requirements before installation.
What should I do if the unit experiences a voltage drop?
Ensure that the load on the 24 VDC and 5 VDC rails does not exceed the 15 A total capacity. Check all backplane connections for secure seating and ensure the grounding path is intact to prevent interference.
