Universal motor with starting current surge limiter - uses controlled rectifier system with blocking up to half wave of supply

摘要

The universal motor has a circuit which limits the starting current. The motor is fed with alternating current and its circuit contains a two pole switch with three positions. The current limiting branch (S) contains a controlled semiconductor rectifier system(TH) and a control circuit. This will enable the semiconductor rectifier system to be blocked in each half wave of the supply voltage at least until the maximum voltage occurs. The control circuit is in parallel with the current limiting branch. It contains a control current branch with a capacitor with a leading control current relative to the supply voltage.