Working Principle of Antipumping Relay

The relay is there to stop coil from unintentional operating of CB due to remaining close pulse after CO operation.

A device that prevents the CB from unintentional operation caused by standing or too long operation command pulses.

There are two types:

a. Prevents the CB to re-close after a CO when the close command is too long or continuous. The anti-pump relay is reset by releasing the close command pulse. After this the CB can be closed again.

b. Prevents the CB to close when a continuous opening command is applied. To reset the anti-pump relay the opening command has to be removed.

When performing a trip-free operation (CO without delay) the open command pulse has to be slightly delayed (10-20 ms) to prevent the anti-pump relay to pick up.