I am trying to do some high frequency dielectric strength testing. Right now, we are using a 500kHz generator capable of outputting ~100Vp-p and running it through a hand wound toroidal transformer. It is working okay but we are having problems with the waveform getting distorted and voltage drop when it heats up (it needs to run for 30 seconds continuously). I'm also having a problem with the insulation on the transformer windings breaking down due to the high voltage using 32AWG magnet wire. We tried with regular and double insulated wire but this is causing the toroid core to heat up enough to melt the insulation. We must also maintain a crest factor of 6 with a tolerance of +-10%. I can not find a suitable ready made transformer or generator with this kind of output. Any equipment suggestions? Also, if anyone has any ideas on how to make a more stable transformer, it would be much appreciated. I'm not well versed in high frequency magnetics.