The scanner is a key part of the Hammond Vibrato system.
The scanner is used in the organ as a single-pole 16-throw rotary switch. It is constructed as a multi-plate air-dielectric capacitor with 16 stator poles and one rotor.
See also HowToRebuildTheVibratoScanner.
_From a 1953 Hammond tech sheet_
The scanner is mounted on the main generator SynchronousMotor and driven at 412 revolutions per minute. Signals coming from the LineBox through the vibrato switch appear on the stationary plates and are picked up, one at a time, by the rotor.
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