How do I use the DRM40 DIN rail redundancy modules current balance feature?

Posted by Martin on August 11, 2020

For optimum longevity, each power supply connected in redundancy should deliver the same amount of current. If power supply “A” delivers 75% of the load and power supply “B” just 25%, “A” will run hotter and have a reduced field life. Electrolytic capacitors are heat sensitive and dry out faster with higher temperatures.

The DRM40 series DIN rail redundancy module should be connected to the power supplies, as follows, with a suitable load.

On the front panel of the DRM module, there is a current balancing status LED. If LED is not illuminated, measure the output voltage on both supplies. Adjust the power supply with the lowest voltage up until the LED turns on. Alternatively, reduce the output of the power supply with the highest voltage.

The current balancing LED will only illuminate when the difference between the input voltages is less than 50mV and the power supply currents will be balanced.

More information about the key features and specifications are on the DRM40 datasheet found via this link: