LOW FREQUENCY POWER SUPPLY FOR ESR FURNACE

Electroslag remelting (ESR) furnaces are used for high quality alloy production with specific features (e.g. electric steel). In course of remelting process a consumable metal electrode is lowered into molten slag layer which in it’s turn melts the  metal electrode.        

TET ESTEL power supply units for ESR furnaces are designed to regulate power and stabilize alternating current flowing through a liquid slag layer.
Low frequency power units are built on reversible thyristor rectifiers consisting of antiparallel connected thyristor bridges with pulse-phase control, switched on alternately.
To compensate for reactive power and increase the power factor as well as to reduce the harmonic distortion factor of the consumed current, capacitor banks maintaining the optimal power factor and controlled by electronic keys are installed at the controller input.
Power supply microprocessor control system enables automatic control of the technological variables (current stabilization at a given level) and dynamic protection from over-current.               

Low frequency power source advantages:       

• Low-frequency power supplies are more expensive than industrial frequency sources, but due to the lower inductive resistance (proportional to the frequency) of the busbars, they improve the energy parameters of the power supply system, especially for high-power furnaces.
• In addition, the undeniable advantage of low-frequency controllers is the symmetrical 3-phase current consumption of the supply network, as well as the low distortion factor of the consumed current due to the use of 12-pulse, 18-pulse or 24-pulse rectification circuits.