The Model 5550 Mechanical Vibration Switch offers basic protection against gross changes in structural seismic acceleration. Its operating mechanism is purely mechanical and consists of a tension spring attached to a pivoting plate on an over-center fulcrum – magnets are not employed. Normally, this plate is in an untripped position. However, in the presence of sufficient seismic acceleration (whether vibratory or impact), the trip plate will pivot beyond this over-center position, snapping to a stable tripped position where it contacts an internal microswitch relay, changing the state
