Safety device for elevator and rope slip detection method using drive sheave acceleration

摘要

In a safety system for an elevator, a safety gear is mounted to a car, the safety gear being electrically operated by an actuator to cause the car to make an emergency stop regardless of whether a running direction of the car is upward or downward. A safety gear controller cuts power supply to a hoisting machine motor and causes the safety gear to make a braking operation upon detection of the slip between the drive sheave and the main rope based on a drive sheave acceleration exceeding a predetermined value.