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the additional Vce threshold of 1.5 makes IGBT's an inefficient choice for low Vce and low Ic vs. MOSFETs at the same cost.
Sort of true but when doing prototyping their ability to take severe abuse more than makes up for a bit of extra loss in lower voltage and current applications.
Personally I use them all the time for any circuit that is going to be working in an abusive electrical applications at more than a few 10's of volts and amps average power levels. To be honest I have found in a number of refit applications switching out power mosfets for IGBT's actually resulted in significantly lower heatsink temps. The forward drop voltage may have been a bit higher but the lower switching losses and robustness more than made up for it in power savings.
**broken link removed**
gary350 Your area of risk is that you want to use industrial scale power via a hobbyist approach with a high chance of hobbyist mistakes causing industrial consequences.
I suggest that you keep the power levels at hobby scale until you have a comfortable grasp of the components, their operating conditions and safety factors. Then scale up.
A little knowledge can be a dangerous thing if it tempts you to take unnecessary risks.
DerStorm8 how did that IGBT work on your Tesla Coil? 15 years ago I learned a Variable Speed Vacuum Fan RQ Spark Gap can be tuned to the correct frequency to get maximum output. Turn the dial and watch the 12 foot sparks get longer and shorter, dial it right to maximum output. Richard Hall said, a rotor is just a fancy toy compared to this. Few people on the TC forum ever took it serious. I have always thought if the spark gap Hz could be tuned to the same Hz as the TC that would be maximum output. I was getting 12 foot arcs from 10kw. I sold all 7 of my TCs, sold the big 10" last summer to the Local University. My 10" PVC pipe actually measured 11.25" diameter with 950 turns of wire 5:1 ratio.
Mosaic, I get the sense that you're underestimating Gary's level of experience. He's not a newbie to electronics--He understands the basic concepts of electricity (ohms, volts, amps, watts, etc) and how they relate, as well as more complicated ideas. He's only trying to learn about more modern components (IGBTs, for example, were developed in the '80s but didn't become common until the '90s, at which time Gary was working with other types of electronics/repair).
I know where he's coming from--Until the beginning of last year I had no idea what an IGBT was either, and only learned because I was building a solid state Tesla coil that required high-power switching devices.
I don't know if Gary feels this way, but it seems to me like you're patronizing him, which is entirely unnecessary.
Well, I do think the OP has inadequate fundamentals since he can't fully understand the TL494 spec sheet and use the very basic oscillator equation. The OP thinks he just needs to bone up on the latest component functions to do the job. Yet he patches entire circuits together piecemeal from different sources, with no analysis evident. I had hoped to reduce his frustration and risk with advice. However, as you are a super moderator I yield to your authority and will desist from my approach.
Its been 15 years since I built a TC I had forgotten about firing the spark gap on the AC peaks so caps have maximum charge. When I turned the variac my vacuum fan speeded up and the output arcs got longer and longer to a point where they stopped getting long. If I continued to increase fan speed output arcs started getting shorter. I must have been dialing in on the AC peaks. This worked good on all my TCs 4", 6", 8", 10" except for the tiny 120 watt TC.