Siemens 6EW1881-6AA SIMATIC S5 Power Supply Unit

The 6EW1881-6AA supplies stable DC voltage to the S5 backplane. This power supply unit fits directly into the standard S5-100U rack. It converts incoming line voltage into regulated 24V DC for all modules. Additionally, it provides the necessary 5V DC for logic circuits inside the CPU.

You can rely on this unit for continuous industrial operation. The 6EW1881-6AA delivers up to 2 amps on the 24V rail. It also offers short-circuit protection and overload monitoring. Consequently, your PLC system remains safe from unexpected power surges.

Technical Specifications and Physical Parameters

This power supply stores a small amount of energy internally. A single electrolytic capacitor provides hold-up time for brief interruptions. The 6EW1881-6AA does not contain any replaceable battery. Below is a complete breakdown of its technical characteristics.

Interface Layout and Connection Details

A single 3-pin terminal block accepts the main AC input. The 6EW1881-6AA features a voltage selector switch on the side panel. Two LEDs on the front indicate “24V OK” and “5V OK” status. A separate grounding screw ensures proper electrical safety during installation.

This unit connects directly to the S5 backplane via a 2-pin power connector. The 6EW1881-6AA does not require any external cooling fan. Passive convection handles all heat dissipation effectively. Therefore, you can mount this module in sealed cabinets without issues.

Operational Benefits for System Reliability

This power supply module protects your expensive I/O cards from damage. The 6EW1881-6AA includes automatic current limiting on both outputs. It also tolerates brief input voltage dips down to 85V AC. Engineers appreciate this robustness for unstable grid environments.