What is current chopping?

Answer 1

When low inductive currents, such as magnetiing current of transformer, shunt reactors are interrupted by breaker, there is rapid deionization of contact space and may cause the current to be interrupted before its neutral zero. This phenomena is called current chopping. This generally occurs during opening small inductive currents by vacuum ckt brkr or air blast circuit brkr. The transient voltage having high restriking voltage RRRV appears across the contacts, unless the arc restrikes. If it restrikes a further, chop may occur or several chops may occur before the current is finally interrupted. Circuit breaker may fail to clear the current.

Circuit breaker in which dielectric strength of contact space grow at slow rat, the problem of current chopping is less severe as the gap breaks down and absorbs successive magnetic energy by restriking. Oil circuit breakers are therefore suitable to such application. This is the reason that sometimes in air blast circuit breakers resistance switching is adopted.

Answer 2

It can be defined as followed. Current with minor fluctuations.