A reduction drive is a mechanical device to shift rotational quickness. A planetary reduction drive is a small scale version using ball bearings within an epicyclic arrangement rather than toothed gears.
Reduction drives are used in engines of all types to increase the planetary gearbox amount of torque per revolution of a shaft: the gearbox of any car is a ubiquitous example of a decrease drive. Common household uses are 
washing machines, meals blenders and window-winders. Reduction drives are also utilized to diminish the rotational swiftness of an input shaft to a proper output speed. Reduction drives can be a gear train style or belt driven.
Planetary reduction drives are usually attached between the shaft of the adjustable capacitor and the tuning knob of any kind of radio, to allow good adjustments of the tuning capacitor with smooth motions of the knob. Planetary drives are found in this situation to avoid “backlash”, making tuning easier. If the capacitor drive provides backlash, when one efforts to listen in a station, the tuning knob will feel sloppy and it’ll be hard to execute small adjustments. Gear-drives could be made to haven’t any backlash by using split gears and spring tension however the shaft bearings need to be very precise.