What is really required therefore is a safe, reliable and inexpensive device, which can be inserted between the transmission line and the consuming apparatus, to convert the high voltage and low current of the economical transmission line into the low voltage and high current〔required by the consuming apparatus that is, a piece of apparatus to perform the same function in electrical transmission that a pair of reduction gears does in mechanic transmission, in which a high torque and low speed are readily and effectively converted into a low torque and high speed, or vice versa.