Elevator Over speed Governor

Elevator Over speed Governor

Over speed Governor is most important in passenger elevator system, its main function is governing the speed of Elevator & it is required to maintain time to time.

It is basically located at Lift machine room, it have a rope witch are connected to the cabin of elevator & at pit it have a tension device to maintain proper tension to the governor rope.OSG have an electrical contact which is activated before mechanical tripping of governor it connected to elevator safety circuit. when elevator cross rated speed of 20% on that case electrical contact will tripped but when it is cross 30% on that time mechanical are tripped.

Basic Diagram of Overspeed Governor system.

When lift is free fall (to the down direction due to gravity) on that case governor will activated & its is tripped to mechanical gripping the governor rope & pull the rope on that case safety gear  are actuated (which mounted in the elevator cabin frame) then stopped to elevator & prevent free fall.

Working principle:- in Modern industry many company are using different types of governor but basic principle is same. it is working on centrifugal force. when governor wheel are rotating above the rated speed on that case synchronisation plate or attached  pendulum are take moment ,on that time the synchronisation plate or pendulum are hit the mechanical cam then cam are hit the attach electrical contact(which may limit switch it not must be auto reset) to disconnect the safety circuit.if speed more then 20% it means then no electrical contact need to that time it is assumes that lift is an safety action.