Trying to resurrect an old, combination, analog volt/watt/amp meter. Traced the problem to a bad 50:5 current transformer (nothing coming out of the secondary taps with a 15 amp load going through the primary donut hole). I want to make sure there are no other problems with this unit before buying a new CT. So I'd like to create an external secondary winding around the bad CT's frame to see if the meter movement operates, but don't know how many turns to use for the proper current ratio. There's only one primary turn (the load wire that runs through the hole). Any help will be appreciated.