The LFD device is designed for heating and drying transformer windings. The principle of the device functioning is based on low-frequency electric currents through the transformer windings and heating these windings to a standard drying temperature of +75… +120°C. Due to the fact that when heated by low-frequency currents, the heat source is the winding itself and the heating comes from the inside, the removal of moisture from the thickness of the insulation proceeds faster and more completely in comparison with other heating methods.

The LFD device can be used in conjunction with the CMM thermal vacuum dryers to improve the drying oil-filled transformers efficiency. In this case during the drying of the transformer there are two simultaneous processes of direct heating of the windings of the disconnected transformer and the removal of moisture which was released from the windings into the oil.

If the oil is drained from the transformer, then it is effective to use the LFD device complete with BV or UVV or Mojave Heat units, which remove moisture released from the windings into the transformer tank.

The process lasts automatically after the windings warming up to a temperature of +75… +120°C until the amount of moisture in the oil becomes less than 10 g/t (ppm).