Yeah, that's one evil load indeed, and I've let out a fair amount of magic smoke with it. A lot less since I went to that BN-pyrex feedthrough design - arcs all gone...probably the biggest breakthrough here so far (even if that's a little embarrassing - I do think there's more to come, though). I should do a better writeup on that - maybe when I have all 10 fingers in typing shape.
Pyrex is the vacuum seal, but importantly is also a voltage dividing resistance used to do field control (differently) on both inside and outside of the tank. BN is what does the real insulating and is bulletproof to hot H ions and other abuse. Everything else is chemically reduced, fails due to internal arcs as it is a dielectric and its own capacitor, or some other failure mode, and I've tried everything except pure alumina (saphhire...) which should work, but as a ceramic it has a binder that will reduce and fail...and sapphire's a little pricey (I thought BN was high...) and kinda hard to make holes in.
I did the fets in my amp way back when for the reason of the more-square safe operating area along with the speed (if you can drive that gate charge, which is the hard part). Outside one app where a guy made a huge ribbon speaker (< 1 ohm) and drove that - no issues, the power supply, a more or less conventional beefy torroid, plus the huge heatsinks...just couldn't muster enough oomph to fry those fets...
Heck, even with real serious fet specs, you can have issues, even with theoretically turning them fully on and off. Those peak currents, stray R and L...my current rig is showing that at some frequencies, where the stepup seems to be acting series resonant - it's pulling the fets out of "full on" to a few volts drop. And these aren't teeny ones.
is what I'm using just now, as turns ratios are right for 30-60v in a full H bridge. And the bigger lower voltage ones are, for this rev, just too hard to drive fast enough. I have a collection and choose based on load, from 048's to 450's.
In a classic case of "what now?" , these huge new batteries came today. Now all I need is some young grunts who want paying work. Someone slipped a digit along the line, and while I paid for 1300 Ah cells, well, these are 1880 Ah. But there's no free still - these also weigh more, around 200lbs/cell. I have to at least get them off the borrowed trailer soon. It'll be nice to finally have "enough, and no compromises" when I also get that additional 1.5kw or so of panels up too, on the roof I have yet to repair.
But maybe the good batteries (which came fully charged!) are a sign of the karma getting back to more normal, which would be a relief.
And the whole mess...
Anybody trying to figure out my taste in music from what I post is in trouble (think Sting's "big house" with lots of rooms)....this was fun, saw it on the Reg the other day:
https://www.youtube.com/watch?v=2cU53wWb6UI
Hopefully some luxury won't punish me too hard. I could use a little just now.
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