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Description
The Siemens 6ES5955-3LF12 is a robust, high-current power supply unit designed specifically for the Simatic S5 automation family. This module is engineered to provide stable, regulated 5 VDC power to central controllers and expansion racks, including the S5-135U, 150U, 155E, and 185U series. It serves as a vital component in legacy industrial control architectures, ensuring that backplane logic remains energized and protected against fluctuations in the primary AC supply.
Features
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High Power Output: Delivers a continuous 40 A at 5 VDC, supporting demanding multi-processor configurations.
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Flexible Input: Supports selectable 115 VAC or 230 VAC single-phase input voltage ranges to accommodate various facility power grids.
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Protection Circuitry: Includes integrated Overvoltage Protection (OVP) and Overcurrent Protection (OCP) to safeguard the rack bus from faults.
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Galvanic Isolation: High-performance isolation barriers effectively decouple the logic rails from AC line noise and field-side disturbances.
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Thermal Management: Features heavy-duty aluminum heat sinks and optimized airflow channels for reliable operation in high-load environments.
Applications
This power supply is intended for use in mission-critical legacy automation systems, such as those found in continuous chemical processing plants, heavy metal rolling mills, and automated container terminal logistics. Maintaining operational spares of this unit is essential for preventing unplanned downtime in systems where S5 controllers remain in active service.
Technical Specifications
| Model |
6ES5955-3LF12 |
| Brand |
Siemens |
| Series |
Simatic S5 (955) |
| Input Voltage |
115/230 VAC (50/60 Hz) |
| Output Voltage |
5 VDC |
| Max Current Capacity |
40 A |
| Operating Temperature |
0 to 55 deg C |
| Storage Temperature |
-40 to 70 deg C |
Installation Guidelines
- Ensure the rack is fully powered down before attempting to insert or remove the power supply module.
- Verify that the voltage selection links are correctly configured for your local AC supply (115V or 230V) before applying power.
- Ensure the module is fully seated in the rack guide rails to maintain proper electrical contact with the backplane.
- Maintain adequate clearance around the module to allow for natural convection cooling through the heat sinks.
- Follow standard ESD precautions when handling the module to prevent damage to internal sensitive electronics.
FAQ
Is this power supply compatible with all S5 series racks?
The 6ES5955-3LF12 is specifically designed for the S5-135U, 150U, 155E, and 185U systems. Please verify your specific rack compatibility before installation.
What should I do if the OVP or OCP triggers?
If the supply latches off, check the rack backplane and connected modules for any short circuits or excessive load conditions. Once the fault is cleared, power-cycling the unit is typically required to reset the protection circuitry.
