Abstract: To control the intermittent movement of a conveyor belt or carousel, fitted with molds, in a unit for the manufacture of moldings from multi-component plastics, an intended/actual value comparison of the speed of the conveyor belt or carousel as a function of the distance of the molds from fixed devices for filling, demolding and similar operations of the molds is carried out so as to provide control signals for the electric motor. The actual value is determined from a signal voltage generated in correspondence with the rotary movement of the electric motor. The signal voltage is additionally, and in parallel to the speed regulation, converted to electric pulses which are summed in their time sequence, as a function of the movement steps of the conveyor belt or carousel, and are compared with a predetermined master function which can be varied.

Abstract: Disclosed is a motor speed detecting device which comprises a first slotted disc (3) having one slot and mounted on a rotational shaft (2) of a motor (1) that is driven by a motor drive unit (7) and a second disc (4) having a plurality of slots, a first magnetic sensor (5) mounted on the first gear (3) in close proximity thereto and outputting two signals with a phase difference and a second magnetic sensor (6) mounted on the second slotted disc in close proximity thereto and outputting two signals with the phase difference and their inverted signals and a detector circuit (8) receiving the output of the first and the second magnetic sensors.