When changing from a dry cleaning operation to a liquid carpet cleaning operation with certain vacuum cleaners, the rotors generally must be changed. This provides more effective cleaning for that specific cleaning operation. Also, the required RPM level of the rotor is reduced, allowing better scrubbing action of the rotor for the latter of the operations. These floor model vacuum cleaners, without a connecting hose, generally use a magnet/Reed Sensor approach because of the simplicity of its design.
This is accomplished by using a Reed Switch, which senses the magnetic field of a permanent magnet. Since the Reed Switch is hermetically sealed, all switching action takes place in a perfectly clean atmosphere, which remains undisturbed by the dusty, dirty environment of a carpet cleaner.
Generally, the permanent magnet is mounted on only one of the rotor assemblies. The rotor is chosen based on what RPM speed is considered the default level.
The Reed Sensor is mounted on the carpet cleaner itself, in such a position to detect the magnetic field of the permanent magnet when its assembly is inserted in the carpet cleaner. The Reed Sensor then detects the permanent magnet, which closes the Reed Sensor contact. This closure then activates the appropriate circuitry leading up to the motor, which in turn adjusts the RPM level. Proper rotor operation is adjusted accordingly and the desired rug cleaning is achieved.