SIEMENS 6ES5951-7LD21

Siemens SIMATIC S5 Power Supply Module

Description

This is the 6ES5951-7LD21, a modular power supply unit designed for the Siemens SIMATIC S5 automation platform. It provides reliable DC power to various S5 racks and modules. With its selectable input voltage and multiple outputs, it is a versatile solution for maintaining and servicing legacy S5-130U and S5-150 series systems.

Specifications

• Manufacturer: Siemens
• Product Line: SIMATIC S5
• Part Number: 6ES5951-7LD21
• Input Voltage: 115V AC / 230V AC (Selectable)
• Input Frequency: 47-63 Hz
• Output 1: 5V DC / 15A
• Output 2: +5.2V DC / 2.5A
• Output 3: +24V DC / 0.35A

Label Info

• TYP (DIN 41752): E220G5/15WRGD
• FACT.NO/FABR-NR: A 3105898

Application

This power supply is specifically used in Siemens SIMATIC S5-130U, S5-150A, S5-150K, S5-150S, and S5-150U programmable logic controller systems. It is essential for powering the CPU, memory, and I/O modules within the PLC rack.

Country of Origin

Made in Germany.

CO2 Impact

By purchasing this pre-owned unit, you are preventing the emission of approximately 120 kg of CO2 associated with the production of a new one. This choice supports a circular economy and reduces industrial waste.

Availability

This is an obsolete item, available from our stock as a tested, refurbished part. Ideal for spare parts or system repairs. Order now from spareparts2day for expert support and fast delivery.

FAQ

How do I correctly set the input voltage on the 6ES5951-7LD21?

The input voltage is selected using the red switch on the front panel. Ensure the system is powered down completely before changing the setting between 115V and 220V AC to match your local power grid.

What is the purpose of the external battery connection (EXT BATT 3.4V)?

The external battery connection is used to supply power to back up the RAM of the CPU module in the S5 rack when the main power is off. This prevents the loss of the user program and data.

Is this power supply compatible with all SIMATIC S5 racks?

This power supply is designed for specific SIMATIC S5 racks, primarily the S5-130U and S5-150 series. It is not compatible with smaller S5 systems like the S5-95U or S5-115U, which use different power supply form factors. Always verify compatibility with your specific S5 central rack or expansion unit manual.

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Last Update: Friday, March 13, 2026