Stage switch changing coils of power electrical transformer - couples adjacent stages to tapping contacts with movable contact engaging common contact and having current limiting resistor.

摘要

A transformer with staged windings is switched by moving a contact pick-up across the winding (TW). Selector connections (M1, M2) extend to the neighbouring tapping points (T1, T2). The connections are coupled to the contents (SA, SB) of a change-over switch (S). The switch has a moving contact (Sm) and a common contact (Sc) coupled to a main stage (H). The neutral point (N) connects to a resistor vacuum valve (W) with a resistor (R) in series. The movable contact (Sm) changes over between adjacent contacts, the current being limited by the resistor. ADVANTAGE - Reduces possibility of contact arcing.