Wiper drive motor, type S9140GXH-TCE, for Hanovia medium-pressure ultraviolet disinfection systems fitted with an automatic wiper. The motor drives the wiper along the quartz sleeve on the cycle set in the controller. The quartz sleeve is the only optical path between the lamp and the water, so any film of scale or iron on its outer surface cuts the delivered UV dose. The wiper sweeps the sleeve on a timed cycle to keep transmission at the design figure. On an automatic wiper the motor works with a limit switch at each end of travel, so a wiper that runs continuously or not at all should be diagnosed at the switch as well as the motor. Reference number 22148-1118.