Induction is something that has nothing to do with gears. It is a property of coils of wire and refers to how much a particular coil resists a change in the flow of current in a circuit. It is measured in Henrys and is really quite interesting.
http://en.wikipedia.org/wiki/Electromagnetic_induction
As for your gearbox I think I remember other teams using this as well to get high reductions but I can't remember any numbers.