A vacuum cleaner motor assembly comprises a motor in a bucket 32, arranged to drive a fan to provide airflow. An epicyclic gear system 34 is attached to the output shaft 33 of the motor, to produce an output of reduced rotational speed. The output is employed to drive an agitator via a belt. The belt is driven at a reduced rotational speed to that achievable hitherto, and thus there is reduced wear on the belt. The provision of a gear arrangement mounted directly to the motor casing provides a compact assembly. One of the epicyclic gears, such as the ring gear 39, is arranged to slip with respect to a clutch member 41 if the agitator becomes jammed. An actuator 50 switches off the motor if the heat of friction of the slipping gear exceeds a predetermined value, or if the slipping gear rotates at a speed above a predetermined value. Thus, the motor switches off before damage occurs to any of the components of the system.