An anti-pumping relay is just an Aux-contactor nothing else, used to protect multiple closures of a circuit breaker.
Anti pumping relay is used to prevent circuit breaker hunting, i.e., continuous opening and closing of the Circuit Breaker. In Emergency mode, a circuit breaker can be opened or closed using a TNC switch (Trip Neutral Close switch)
The anti-pumping relay primarily Prevents the repeated closing signal to the closing coil after the successful completion of the closing operation.
The anti-pumping relay allows the breaker to close only once for each press of the 'close' push button or TNC Switch. If a fault exists on the circuit before the breaker is closed, the breaker will close and immediately trip before the operator has a chance to release the close button (or handle). The anti-pumping relay prevents the still-active close signal from trying to re-close the breaker. Many breakers are not rated for multiple successive re-close operations. If an anti-pumping relay is not used, the rapid close open-close-open... series can result in the destruction of the breaker and harm to the operator.