Use a portable light transformer to dry a damp voltage transformer circuit

Once the voltage transformer TV gets damp or water seeps, it will no longer work properly. If combined with the vacuum degassing method and using a portable lamp transformer to energize the winding of the voltage transformer to heat and dry it, the TV insulation resistance can be increased to a qualified value, as shown in the circuit in the figure. The specific method is: first drain the insulating oil of the voltage transformer, and use a vacuum pump to degas, so that the moisture is discharged by the vacuum pump. Then energize the windings 1a to 1x of the voltage transformer TV, heat and dry them, and short-circuit the high-voltage windings A to The low-voltage windings 1a~1x of the TV are connected to the 12V block of the portable light transformer T. Close the knife switch QS and adjust the voltage regulator TA so that the current of the ammeter AP is about 30A. At this time, it should be noted that the winding temperature of the TV should not exceed 80oC. The temperature should be tested every 15 minutes, and the temperature should not rise too fast. It is ready when the insulation resistance value rises to the qualified value.