Correct AnswerB. It balances the weight of the lift car and a portion of its load to save energy
Quick Explanation
The counterweight balances the lift car plus a designed fraction of rated load, reducing the traction motor torque and energy needed to move the system. It also helps maintain traction on the sheave.
Detailed Explanation
Concept & Reasoning
In a traction lift the car and counterweight are connected by ropes over a drive sheave. A common design balances approximately car mass plus 40–50% of rated payload, although exact balance factor varies. The motor then primarily handles the difference between car-side and counterweight-side weights plus losses/acceleration.
How to Solve It in the Exam
Counterweight reduces unbalanced load on the motor.
Important Exam PointCounterweight is not the emergency brake; safety gear/governor handle overspeed protection.
Related Revision Path
This question sits in the revision path Building Electrical Services → Vertical Transportation → Traction Elevators .
