1. A drive for an escalator for driving a stair chain and arranged on at least one side of an escalator at an end thereof, the drive comprising a main drive wheel, characterized in that several connecting openings are arranged in a main gear housing and at the circumference of the main drive wheel, and at least one drive unit are mountable to the connecting openings and are in drive connection with the main drive wheel, wherein the connecting openings at the main gear housing are formed and arrayed to be coverable when a drive unit is not mounted thereto, each of said drive units comprising a motor, gears for coupling said motor to said main drive wheel, and a brake.
2. The drive according to claim 1, characterized in that the drive units each include a clutch.
3. The drive according to claim 1, characterized in that the drive units each include a torque transmitter.
4. The drive according to claim 1, 2 or 3, characterized in that a common frequency-setting device is provided for the feed and control of each of the motors of the drive units.
5. The drive according to claim 4, further comprising data, speed and torque transmitters associated with each of said drive units, and a common control and regulating unit for the processing of data from said transmitters into output data for the control of relays, the frequency-setting device, optical signals, illumination and a relay control.