I have the crazy idea of winding a PT from scratch. I unwound a donor PT because it had a short in at least one winding and the HV secondary put out 1200V. The HV winding was under the primary so I've got to wind from former up. Now, in looking through various texts the one item I'm going to have to guess at is the 'lines of Flux' or Flux Density of the laminations from the PT. I've seen values of 55000,60000,75000 and up to 120000 in books and online texts and the calculations for winding turns and turns-per-volt vary widely with small changes in the flux amount. Is there any possible way to determine this information without knowing who supplied the iron?