A method for heating encapsulated gas filled three phase power switches has three resistance heaters switched between delta and star connection by thermostats

摘要

Gas filled encapsulated power switches have to be maintained at a limited temperature range. Resistance heaters (2) are connected to three phase electrical mains supply (L1,L2,L3) through switches actuated by relays (6,7) to connect in high or low output conditions according to the temperature.