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Old 08-27-2014, 02:50 PM   #1021 (permalink)
MPaulHolmes's Avatar
Join Date: Feb 2008
Location: Maricopa, AZ (sort of. Actually outside of town)
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Michael's Electric Beetle - '71 Volkswagen Superbeetle 500000
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They go down to a LEM 50, which would be a LEM 25 with a single loop of wire. Its just that I just got done spending like $200 on 6 of those. haha. The LEM 50 has a range of -150Amp to 150Amp. But I don't know if it stays linear through that whole range. -100 to 100 would be a safer bet. It also needs leeway for startup surges not tripping the hardware overcurrent. A LEM 150 might be good. Then, the hardware overcurrent wouldn't trip until +/-300amp (that's the resistor values I picked. For it to trip at double the lem rating). The resolution would be around 128 ticks of the A/D corresponds to 150amp. I think I'll get a couple LEM 50's for testing. Actually, one of the beta testers has a rewound motor for a lower voltage, which would mean a high current anyway, so at least his LEMs aren't a problem. And depending on thingstodo's motor choice, I could get different LEMs for him to suit the motor. I can always use the leftover LEM 300s for other stuff later. Those are what I used in the DC controllers.

I think spread spectrum switching will work really well. It's working in a beta tester's DC controller up in Olympia, WA.

EDIT: That's a good idea about squarifying (I declare that to be a word!) the wires. I have a sheet metal bending machine that I can squish stuff with. Actually, if I squash them flat I bet I could get 3 #6 loops.

kits and boards

Last edited by MPaulHolmes; 08-27-2014 at 02:58 PM..
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