A winding drum elevator has a gear-reduction drive machine that is usually located at the top of the elevator shaft. Two steel ropes wind onto a large drum. The ropes extend from the car over sheaves, pulleys with grooves around their circumference that grip the ropes. The ropes run up the hoistway to the sheaves, down to the drum, around the drum several times, off the back side of the drum, against a deflector sheave, back up the hoistway, over another sheave, and down to a counterweight.
The motor turns the sheave in one direction to raise the elevator and in the opposite direction to lower it. When the car goes up, the counterweight descends. When the car goes down, the counterweight is raised. Many winding drum elevators also have two separate ropes that connect the top of the car to sheaves at the top of the hoistway and down to a separate section of the counterweight.
The sheaves, motor, and control system are generally housed in a machine room at the top of the shaft. The car and counterweight ride along guide rails on the sides of the shaft that prevent them from swaying and stop the car if there is an emergency.
A winding drum elevator has several standard safety features, including an overspeed governor to stop the elevator if a rope breaks. It also has upper and lower terminal limit switches, an automatic car lowering device, an automatic battery lowering device, and an emergency manual lowering device.
It may be necessary to do some excavation to install a winding drum elevator. While a winding drum elevator is generally less expensive than a hydraulic model, the cables need to be replaced every three to five years. Winding drum elevators are noisier than other types of elevators and not as smooth, but they are more versatile and efficient than hydraulic elevators and generally have more safety features.