Re: Transformers

Steve writes...

> What is the best way to try to see if a transformer (pole or potential) 
> is good using only a DVOM?  Is it just a matter of making sure the 
> terminals aren't open circuited, and that the LV and HV sides aren't 
> shorted together (assuming they're really not electrically connected), 
> or is there more to it than that?

A few ideas from me (NOT an exhaustive list) :

Check the turns ratio using a 50/60Hz signal from a signal generator
Check for o/c windings
Check for pri leakage to case - a megger should be adequate for the
      low voltage side
A DVOM measuring in the 10's of MOhms range is OK for a cursory look-
      see for pri/sec leakage but not a definitive test where 20kV+ of
      isolation is concerned.
A winding resistance check is probably a worthwhile exercise

An idea might be to contact a power utility or transformer company 
and find out what tests they do. They probably have a printed schedule