Vacuum Motor
The output shaft (or stem) of the vacuum motor is spring-loaded to its extended position, and is moved inward by vacuum from the transducer. The various movements of the vacuum motor stem controls the position of the output shaft of the programmer, the programmer vacuum valve, the amplifier feedback potentiometer and the blower speeds. In order to prevent the loss of position during stop/restart operations, a restrictor is added in-line between the vacuum checking relay and the transducer. This is a sintered, plug-in-hose disc.