The Siemens 6ES5955-3LF12 is a robust, high-capacity power supply unit designed for the Simatic S5 automation system. It serves as a critical component for powering central controllers and expansion racks, including the S5-135U, S5-150U, S5-155E, and S5-185U series. This unit ensures reliable operation by converting standard 115 VAC or 230 VAC mains input into a stable 5 VDC logic supply, capable of handling high-current demands in demanding industrial environments.

Features

• High Current Capacity: Delivers up to 40 A at 5 VDC for complex backplane configurations.
• Flexible Input: User-selectable input voltage settings for 115 VAC or 230 VAC operation.
• Protection Circuits: Integrated overvoltage (OVP) and overcurrent (OCP) protection to safeguard backplane components.
• Galvanic Isolation: High-barrier isolation between input mains and internal logic rails to mitigate field-side electrical interference.
• Thermal Management: Heavy-duty aluminum heat sinks designed for efficient heat dissipation within standard rack-guided airflow channels.

Applications

This power supply is engineered for legacy Simatic S5 systems found in heavy industrial sectors, including continuous chemical processing plants, automated container terminals, and metal rolling mills. It is essential for maintaining system integrity and preventing downtime in legacy control architectures.

Technical Specifications

Installation Guidelines

• Power Off: Always disconnect the main power source before installing or removing the module from the rack.
• Mounting: Ensure the unit is securely seated in the designated chassis slot to maintain proper electrical contact with the backplane.
• Ventilation: Do not obstruct the airflow channels; ensure adequate clearance above and below the unit to allow for natural convection cooling.
• Grounding: Verify that the rack chassis is properly grounded to prevent electrical noise and ensure safety.
• Input Configuration: Confirm the input voltage link settings match the local supply grid before applying power.

FAQ

Is this power supply compatible with all S5 racks?

This model is specifically designed for the S5-135U, S5-150U, S5-155E, and S5-185U configurations. Please verify your specific rack model before installation.

What should I do if the power supply trips?

The unit features internal protection. If it trips, check for short circuits on the backplane or excessive current draw from connected modules. Ensure the input voltage is stable and within the specified range.