Electric furnace transformers are part of electro-thermal installations, such as electric furnaces and electric heating devices, used for producing ferrous, non-ferrous and rare metals and their alloys with given properties.
The specifics of operation, modes of operation and technical requirements make these transformers a separate class of power transformers.
The most significant features of electric furnace transformers are:
· LV currents can be in the tens of thousands of amperes
· Numerous ignitions and arc interruptions on the electrodes in arc furnaces cause abrupt changes in the current in furnace transformers, resulting in electrodynamic effects and overvoltages in the windings
· Frequent switching by HV-side circuit breakers, especially with vacuum arc-quenching chambers in on-load tap-changers, are also sources of overvoltages
All these factors impose additional requirements on the design of furnace transformers.
ETD produce electric furnaces transformers with output up to 80 MVA.