Power Transformer Dryout

[littledon]

I need to dry out an old transformer and extend the life. Test indicate moisture/contamination in the windings. We have a trailer mounted purifier/vacuum rig. I am not sure that our procedure is adequate. Does anyone have a proven procedure to dryout a transformer using a trailer mounted vacuum/purifier rig?

 

[stevenal]

Your rig can dry the oil but not the paper. Velcon Superdri equipment is used for this purpose.

 

[CarlPugh]

If dryout time is not important, you can probably dry out the transformer. (My guess is that it would take weeks to dry out the transformer) Dry oil adsorbs moisture from the insulation and this is a slow process.
Contact the manufacture of the vacuum/purifier rig and see what they says about drying out transformers.
Also contact the transformer manufacture, they may have some instructions on drying out the transformer.
Drying out a high voltage transformer is a complicated process and if you have no experience, I would recommend contacting a company that specalize in drying out/re-conditing transformers.
Somewhere I have a Westinghouse manual on oil filling their high voltage transformers. If you think it would be helpful, will try and locate it.
Good Luck

 

[tinfoil]

Links:

BIG file (8MB), much useful information, a bit of a sales pitch:

http://www.cjc.dk/assets/1086690000Transformer_Life_Extension_web.pdf

http://www.electricity-today.com/et/issue0503/onine_dryout.pdf

http://www.vaisala.com/DynaGen_Attachments/Att21493/VN160_p18_21.pdf.pdf

 

[Torricelli]

specialists are listed under

http://www.vacuum-guide.com/firmenlisten/produkte/vacuum_impregnation.htm