An elevator safety circuit for an elevator system in which an output is arranged to selectively provide an electrical current from an input to an electromagnetic brake coil via a current flow path. An actuator transistor is arranged in series along the current flow path between the input and the output, the actuator transistor being arranged to selectively allow passage of the electrical current. A controller is arranged to carry out a test operation when the braking element is in the open position. The test operation comprises operating the actuator transistor in its disabled mode for a time period, monitoring the electrical current through the brake coil, and determining whether the magnitude of the electrical current reduces during said time period, the time period being selected such that the magnitude of the electrical current remains sufficient for keeping the braking element in the open position during the test.
ELEVATOR SAFETY CIRCUIT
2022-01-20
Patent
Electronic Resource
English
IPC: | B66B Aufzüge , ELEVATORS |