What type of elevator system uses a counterweight?

A traction elevator system uses a counterweight to assist in the movement of the elevator car, significantly enhancing its efficiency. In this system, the elevator car is connected to a counterweight by steel ropes that run over a sheave (or pulley). The counterweight balances the weight of the elevator car, which reduces the amount of energy required to lift it. As the car ascends, the counterweight descends, and vice versa, which helps in minimizing power consumption by the motor.

In contrast, the other types of elevator systems do not utilize a counterweight in the same way. Pneumatic elevators rely on air pressure to move the cab, hydraulic elevators use fluid pressure to lift the cab directly via a piston, and rope-less elevators operate using magnetic levitation or linear motors, which eliminates the need for traditional counterweights found in traction systems.