General protection relay (WS) of AE-SW type Air Circuit Breaker has tripping characteristic and function for general use. However, we also provide the replay having the special tripping characteristic to protect generator(WM) since ACBs are often used in the generator circuit. WM relay is set at the factory with the specified value in accordance with the rated current and the overload characteristic of the generator, long-time delay current (IL) and the tripping time with 120% of IL is adjustable.