Parallel use for redundancy

It is possible to connect power supplies in parallel for redundancy operation in order to achieve better system availability. Redundant systems provide a certain amount of additional power to operate the load when a power supply unit fails. The simplest method is to connect two power supplies in parallel. This is called 1+1 redundancy. If one power supply fails, the other can automatically supply the load current without interruption.

The 1+1 redundancy allows ambient temperatures up to +70°C.

	Notes on parallel use for 1+1 redundancy Be sure to use a redundancy module in order to decouple devices from one another. This prevents the defective device from becoming a load for the other device and the output voltage no longer being maintainable. Note that leakage current, EMI, input inrush current and harmonics increase when using multiple devices.

Recommendations for the construction of redundant power supply systems:

Power supplies that contain a DC-OK signal contact are best suited for the construction of redundant power supply systems.

Use this DC-OK signal contact to monitor the individual power supplies.

Use separate grids for each power supply whenever possible.
It is recommended to set the output voltages of all devices to the same value (± 100 mV) or to leave them at the factory setting.

Wiring example:

Parallel use for redundancy 2: — Wiring for 1+1 redundancy with a PS9401-2440-0000 redundancy module