摘要 |
An elevator system having an elevator car, a DC drive motor for driving the elevator car, an adjustable voltage DC source for the drive motor, overvoltage and overacceleration detectors responsive to the armature voltage of the drive motor, test apparatus for testing the operability of the detectors during each run of the elevator car, and a protective circuit. The protective circuit initiates an emergency stop of the elevator car in response to overvoltage, or overacceleration, and it prevents the elevator car from starting a new run when the test apparatus detected a malfunction during the prior run. |