Siemens 6ES5955-3LC41 Power Supply Module for SIMATIC S5

Core Power Conversion for SIMATIC S5 Systems

The Siemens 6ES5955-3LC41 is a modular power supply unit for the SIMATIC S5 PLC family. This module converts AC line voltage into regulated DC power for S5-135U and S5-155U central racks and expansion units. It delivers stable 5V, 12V, and 24V DC outputs to power processors, I/O modules, and memory submodules . Consequently, it is a foundational component for reliable S5 system operation.

Output Specifications and Compatibility

This power supply provides a robust 5V/18A output for the main backplane bus. It also supplies auxiliary voltages for sensors and communication modules. The 6ES5955-3LC41 connects to the rack via an 8-pin connector for 5V power and a 37-pin connector for control signals . It accepts both 230V AC and 115V AC input with simple jumper configuration. Furthermore, it includes two integral fans with airflow monitoring for thermal protection.

Technical Specifications and Battery Information

This module incorporates a battery circuit for RAM retention in the CPU and memory cards. Compatible backup batteries include the 6ES1000-7AA type . The power supply’s successor is the 6ES5955-3LC42, which offers the same functionality . The following table details its key functional parameters.

Application in Legacy S5 Support

Plant engineers rely on this power supply for continuous operation of S5-135U and S5-155U controllers in production environments. The fan monitoring system will trigger an alarm and shut down the 5V output if it detects a fan fault . The Siemens 6ES5955-3LC41 is essential for maintaining S5 automation systems where legacy equipment remains in service. Therefore, sourcing tested replacement units is crucial for lifecycle management in manufacturing and process industries.