Antipumping

A "Search all of CR4" probe might well turn up the CR4 thread within the last week on this same subject. Even Google will likely catch it, too.

http://cr4.globalspec.com/thread/55141

http://cr4.globalspec.com/thread/13634/Antipumping-Contactor-use

http://cr4.globalspec.com/thread/25923/antipumping-relay-in-CB

http://cr4.globalspec.com/thread/75409#comment819487

This feature keeps one from resetting a circuit breaker too soon or too repeatedly into a continuing fault condition.

To prevent "pumping" repeated close signals inadvertently to the closing coil of a circuit breaker. Imagine a scenario, wherein there is an existing fault and the operator - unaware of the fault - attempts to close the breaker, by pressing the close push button or by turning the T-N-C Switch to the 'C' position. The breaker will attempt to close but the protective release would sense the fault and would trip the breaker. All this would happen within 100 milli seconds (assuming a closing time of 60 milli seconds and an opening time of 40 milli seconds). And, it is humanely impossible to release the hand from the close push button or the T-N-C Switch, within this 100 milli seconds. Thus, the closing signal would persist and the breaker would attempt another closure - under fault conditions. Most of the circuit breakers would not withstand such closing-under-fault conditions, twice in succession. The anti-pumping relay would prevent a second closing signal to the breaker closing coil, even if the Push Button/T-N-C Switch is kept pressed, thus avoiding the above danger.