SIEMENS 6ES5951-7LD21
- By SIEMENS
- Part #: 6ES5951-7LD21
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Siemens SIMATIC S5 Power Supply 6ES5951-7LD21
Description
The Siemens 6ES5951-7LD21 is a power supply module for the legacy SIMATIC S5-115U PLC system. It provides reliable and regulated DC power to the CPU and I/O modules within the S5 rack. With a selectable input voltage of 120V or 230V AC, it offers flexibility for various industrial environments. This module is a crucial component for maintaining and repairing existing S5 automation systems, ensuring their continued operation.
Specifications
- Manufacturer: Siemens
- Series: SIMATIC S5
- Product Type: Power Supply Module
- Model: 6ES5951-7LD21
- Input Voltage: 120V / 230V AC (Selectable)
- Output Voltage 1: 5V DC / 15A
- Output Voltage 2: 5.2V DC / 2.5A
- Output Voltage 3: 24V DC / 0.35A
- Compatibility: SIMATIC S5-115U PLC Systems
Label Info
- Part Number: 1P 6ES5951-7LD21
- Serial Number: Q6 F1414268
- DIN Standard: DIN41752 E230G5/15 WRGD
Application
This power supply is specifically designed for use in Siemens SIMATIC S5-115U racks, powering a wide range of automation applications in manufacturing, process control, and building automation that still rely on this robust legacy platform.
Country of Origin
Made in Austria.
CO2 Impact
By purchasing this used power supply, you are avoiding the production of a new one, saving approximately 80 kg of CO2. This is equivalent to the emissions of driving a car for 400 kilometers.
Availability
This is an obsolete item, available as a refurbished or used part. Stock is limited. Order now from spareparts2day for expert support and fast delivery.
FAQ
Is this power supply a direct replacement for the 6ES5951-7LD11?
Yes, the 6ES5951-7LD21 is the direct successor to the -7LD11 and is fully compatible. It can be used as a drop-in replacement in any S5-115U system.
What is the purpose of the battery compartment on this S5 power supply?
The batteries are used for buffering the RAM of the S5 CPU in the event of a power failure. This prevents the user program and data from being lost. It is crucial to check and replace these batteries periodically.
Can I use this power supply in a modern SIMATIC S7 rack?
No, this power supply is specifically designed for the SIMATIC S5-115U series. It is not mechanically or electrically compatible with any SIMATIC S7 racks (S7-300, S7-400, S7-1200, or S7-1500).
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Last Update: Friday, March 13, 2026
