OK just tried one of the smaller gauge cmc's i pulled from the second psu, there 2 lots of 28turns, so i put these in series and wound 10 turns with a 5 turn tap for the secondary. On power up it would run but the thyristor would latch at a relatively low voltage, but something very strange happening which i am quiet excited about, i am scoping primary and secondary, when it latches up sometimes when i switch off the power supply i get 4 or 5 bursts on the secondary of about +/- 10V pulses, but nothing on the primary, how weird is that, i say i am excited about this, i guess it could be noise causing spurious data in the dso, but i have seen these +/- pulses before and they were a lot harder to get to appear and then not in an orderly fashion I have stopped testing for the night, i don't want to disturb anything until i bring my camera home so i can film the pulses to see what everyone thinks, i will also bring my non PC based scope home to confirm this see's them. So how can i have high current pulses, when the primary shows no drive and remember this happens when i power off the latch up condition by switching the psu off. EDIT thinking about this, it cannot be noise on the dso because i am only seeing the spikes on the Chan that's connected to the secondary, i am getting really excited about this. During latch up i monitor the voltage coming out my psu and it only reads about 10-18V this is being pulled down by the latched on thyristor, i think it was 10-18V maybe it was lower, i will check this again when i get my camera
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