A low energy mechanically driven and electromagnetically actuated ground fault trip indicator is taught. The ground fault trip indicator utilizes the magnetic flux of a permanent magnet in a first flux path to maintain a movable armature biased against a spring. An electromagnet is disposed to provide...http://www.google.com/patents/US4157520?utm_source=gb-gplus-sharePatent US4157520 - Magnetic flux shifting ground fault trip indicator
