Starting circuit for DC motor in toy - superimposes extra voltage on full-wave voltage used for max. speed

摘要

The starting circuit for e.g. motors in model trains, employs half-wave voltage to the motor and then changes to full-wave voltage for running at max. speed. An extra voltage is superimposed on the variable full-wave voltage. This extra voltage is taken from the same winding (1a) as the full-wave voltage via a fixed or variable tapping on this winding. The transformer has sliding contacts acting as a current pick-up (2). The current pick-up has a third sliding contact (2c) moving along part of the same path as the other two sliding contacts.