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Re: Quarter shrinker resistors
I don't use a charging resistor in my system since its powered from a 15/60 NST and FWB rectifier through a HV switch that is opened before firing. I use a 10kV 1A fuse instead of a charging resistor to protect the NST windings in case a rectifier shorts out.
My bleeder resistors consist of five 20K 225W wirewounds in series. These are switched across the capacitors (via another HV relay) when the unit is fired, and the bleeders are always connected across the caps except when charging. I also use a passive current monitor circuit (zener, LED, and Sonalert) that provides visual and aural warnings whenever there's significant bleeder current flowing after a shot.
The wirewound charging and bleeder resistors you plan to use should work fine - they're inexpensive and will take quite a beating.
For your quarter shrinker, what resistors are you using for the charging resistor and discharging resistors? I am considering 5K ohms at 225 watts for the charging resistor and 35K ohms (5K x 7 units at 225 watts each).
Thanks for the info. I have decided that the current-limiting resistor will not really protect the NST secondary in the event of a FWB failure unless I use an absurdly high resistance high wattage HV resistor. I like your fuse idea. I looked on E-Bay and found a 15.5 KV 0.5 amp resistor, but they want $70 for it. I will pay it if I have to but I am looking for another source. Where did you get your fuse?
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