Date: November 2010

Company: ET / RANCAGUA – VI Region.

We worked to inspection and realize a diagnose to interior mining transformers:

– Visual inspection of the transformer.

– Measurement of the resistance of medium voltage coils in all taps.

– Measurement of the resistance of low voltage coils.

– Measurement of the resistance of insulation.

– Removal of 200 l. of silicon to inspection the interior of the transformer.

– Removal of the lid perneria and after the removal of the interior inspection of the transformer to confirm:

– Internal short circuit is evident in tap changer (phase 3)

– Deterioration of the primary and secondary enrols. (phase 3)

– Silicon with presence of charcoal because of short circuit.