This article introduces a new contravariant bridge circuit in the power source of the medium friquency induction furnace,analyzes the necessity of using R-C for protecting the thyris-tors.

• 介绍一种新型晶闸管中频感应电炉的逆变电桥，分析了对该电桥逆变晶闸管采用阻容保护电路的必要性。