<I've seen mention on this list of Rauch trying to blow himself up doing something with resonant chokes, but I <wasn't privy to the actual event. What was the story there?
<73
<Randy
<KZ4RV
##? simple really.? His choke resonated at aprx? 117hz- 119hz..with just bleeder load.? Once the real load was
applied, the choke XL? drops a tiny bit... and? resonance? freq? increases a bit.? ?Once it hit? 120 hz... with a load on it,? all hell broke loose.??
##? He was? using the? classic? ? resonant choke - filter cap? config.... like henry radio and collins used...except they resonated on the high side of? 120 hz....? which increases in freq? even more..with? max load.?
##? In the above? resonant choke - cap? config, the? resonant choke is getting hammered? by? 60% ripple, coming out of the? rectifiers.? ? And the? ripple freq? coming out of the? rectifiers is? 120 hz...or? 2F.?
##? Think? of how parallel? resonant traps? work on a triband? yagi.? ? You end up? with? extremely high peak? V on the capacitor section of the trap....and extremely high current? flowing through the coil.? ?When the sign wave flips? polarity,? you get a huge? back emf from the coil..which charges up the cap.? ?The cap then discharges through the? coil..producing? high currents through the coil.? ?It just goes back and forth forever? ( with power applied..and a big load).?
##? The other issue with the classic? resonant choke - Cap? ?setup is the B+? is only .9 X xfmr sec.?
Henry radio used a 6000 vac? sec on it's? 8K ultra....fed into a FWB.... then into the resonant choke - cap? filter..and a big 300 watt? bleeder.? ? The 8 K ends up being just? 6000 X .9 =? 5400 vdc.... no load.? ?Which drops down to? 4800 vdc? with a 1.25A? load.? 6 kw dc input..and? 3.5 kw? rf output.? ?So it drops? 600 vdc... which is nothing to? write home about.?
##? A? 3600 vac sec? with a FWB..or a 1800 vac sec? and a? FWD? ?would have done the job... and a C input filter.?
##? Put the? $$$? into the xfmr.... not a? choke.??
Gotta run, a ton of stuff going wrong this AM.?
Jim? VE7RF
