NEIEP Mechanics Practice Exam

What effect does the loss of traction between hoist ropes and the machine driver have when the counterweight lands on its buffer?

1. It causes the elevator to stall

2. It prevents the elevator car from being flung into the overhead

3. It increases wear on the hoist ropes

4. It enhances the elevator speed

The correct answer is: It prevents the elevator car from being flung into the overhead

The effect of the loss of traction between the hoist ropes and the machine driver when the counterweight lands on its buffer is best understood in the context of the system's safety and operational stability. When the counterweight comes to a sudden stop, significant forces act on the hoist system. If there is adequate traction, the hoist ropes will transfer the load more effectively, allowing for smoother movement and deceleration of the elevator car. In the case of reduced or lost traction, however, the elevator car can experience a more abrupt change in motion. This lack of proper engagement between the ropes and the machine driver helps prevent excessive force from being transferred to the elevator car and could help avoid a situation where the elevator car is flung upwards into the overhead space. This is crucial for maintaining the safety and integrity of the elevator system, as it mitigates the risk of mechanical failure or damage caused by an uncontrolled movement. Hence, this understanding substantiates why the loss of traction effectively prevents the elevator car from being flung into the overhead, ensuring smoother and safer operation during sudden stops or changes in load conditions.