摘要 |
Elevator brake or other drag is checked by establishing (10-13) baseline motor currents at plural determined positions as the car is moved up and down both empty and with full load. In a normal run (21), the load is recorded (22) and the motor current required to drive the load at rated speed at the next determined position is both predicted (28) and measured. If the difference between the predicted and actual current exceeds a tolerance (33, 34), the car stops at the next floor (35), the system is shut down (39) and a message generated (40). When the brake is in proper operating condition, baseline motor current required to move a car with the brake engaged is recorded. Thereafter, a high fraction (such as 90%) of baseline motor current is applied to attempt to move the car. If the car moves, the system is shut down (101) and a message generated (102).
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