[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

SSTC Progress I think:^)



Original poster: Robynsaddiction-at-aol-dot-com 

Well, let me start by saying that I am not sure that you (the list) will be 
able to contact me through the list, because I have AOL and it is giving me 
a hard time with the list. My email is Robynsaddiction-at-aol-dot-com (pleas 
contact me through my email). Anyhow, I decided to build my own board 
rather than use Jim Mitchell's board, and while I was at it I built a new 
half bridge. I get nice square waves from the TC4420's and 29's. I have 
appropriate GDT material, and get a differential voltage of 26 volts p-p on 
the MOSFET's. However, when I look at the output of the gate drive chips 
when the 100k pot is turned anywhere other than 0 ohms the waveforms start 
to distort. However, this may just be due to my crazy scope. Anyhow, I put 
it all together, and am able to get about 2-3 inches worth of spark with a 
half wave rectified DC of about 50 volts. Above that and something in the 
bridge dies:^( I tried using full wave rectified DC with 10,000uF of 
filtering, and it made the output much bushier. Though, when I went above 
50-60 volts DC in this configuration the MOSFET's blew like M-80's, caught 
fire, and almost destroyed my board. Needless to say, the heat sink of the 
FET's was steaming hot. So, what is my problem? Am I tuning incorrectly? I 
kind of think that I may be tuning the thing incorrectly. I have the 
MOSFETs on the same sink, but they are isolated by heat conducting pads. By 
the way, this is a coil is a design like Steve Ward's 1st feedback SSTC, 
only his actually worked. Anyhow, yeah, what is going on here? I am so 
excited to think that I might actually be just a few small mistakes from a 
working SSTC of my own.Thanks List, Richard Harris