Siemens 6ES5955-3LF42 Power Supply Module SIMATIC S5

Technical Overview

The 6ES5955-3LF42 power supply module provides stable DC voltage for SIMATIC S5-95U and S5-100U systems. This module converts the incoming AC mains supply into regulated 24V DC output. It delivers up to 2.5A of continuous current for powering the CPU, I/O modules, and field devices. The integrated short-circuit and overload protections ensure safe and reliable operation in industrial environments.

Key Technical Specifications

Parameter	Specification
Brand	Siemens
Model Number	6ES5955-3LF42
Product Type	Power Supply Module
Series	SIMATIC S5
Input Voltage	AC 120/230V (selectable)
Output Voltage	DC 24V
Output Current	2.5A continuous
Protection	Short-circuit and overload protection
Ripple	< 50 mV (peak-to-peak)
Efficiency	Approx. 85%
Approx. Weight	0.8 kg

Power Conversion and Regulation

The 6ES5955-3LF42 converts AC mains input to a stable 24V DC output. It maintains tight voltage regulation even under fluctuating load conditions. The low output ripple ensures reliable operation of sensitive electronic modules.

Protection Features and Reliability

This power supply includes electronic short-circuit protection on the output. It also limits the output current during overload conditions to prevent damage. These safety features reduce downtime and protect expensive downstream components.

Compatibility and Installation

The module plugs directly into the S5 backplane or mounts on a standard 35mm DIN rail. It supplies power to all modules in the rack via the backplane bus. Users can quickly replace the unit without rewiring the entire system.