Tap changing system for power transformer with high switching capacity - has series connected sections of damping resistance contacts each containing resistance parallel to contact

摘要

The tap changing system is used on a regulating transformer with two main and two parallel resistance terminals. The resistors are connected to the second set. A high switching capacity is achieved even when there is a high inductance between the selected stages, without inserting damping resistors. The resistance contacts (4, 5) on each side consist of two series connected switching sections (15, 15') with permanently connected resistors (16, 16'). The operations of the contacts are synchronised. There is a time delay of up to three half waves between the closure of the resistance contacts and the opening of the main contacts.