What is the purpose of an elevator's counterweight?

The purpose of an elevator's counterweight is to balance the weight of the elevator cab. By using a counterweight, the system achieves equilibrium, making it easier for the motor to lift the cab. The counterweight is typically designed to match the weight of the empty cab plus a portion of the maximum load the cab is intended to carry, which helps to reduce the overall energy required to operate the elevator. This balance minimizes the strain on the motor, increases efficiency, and contributes to smoother and quieter operation. By having a counterweight, the system can benefit from gravitational forces, which help lessen the load the motor has to exert when moving the elevator up or down.