• A "hydraulic" elevator utilizes a motor and a pump to raise the piston out of the ground pushing the elevator up and down the shaft. It uses an electric valve to control the direction and speed of the piston. • A "traction" elevator uses sheaves and cables to move an elevator up and down the shaft. It utilizes a counterweight that balances out the load so that the motor does not have to work as hard. The motors can be either AC or DC depending on the type of drive or generator the elevator uses to convert building power into controllable power to move the elevator.