If you are using a DC motor with brushes they can have a leak to frame through the carbon dust. Blow it out good.
Sent from my iPhone > On May 2, 2020, at 2:54 PM, Mr. Sharkey via EV <[email protected]> wrote: > > The usual instrument for measuring insulation leakage is called a "megger" > or "hipot tester". This can give you a quantified value of the leakage in > ohms-per-volts. Most any motor shop will have one, and can test for you. > > Finding your fault is likely going to me more involved even if you buy or > borrow the megger. I sniffed for leakage in my hydroelectric generator wiring > by building a GFCI tester out of the cord from an old pressure washer and a > light bulb, and went looking for the fault. It's a go/no go proposition, > disconnecting parts of the circuit and testing, repeating as many times as > necessary until you stop getting trips. > > In your case, since you aren't getting consistent tripping, you either need > to find a GCFI that trips consistently and use that to test, or increase the > amount of leakage in the test circuit to just below the threshold of > tripping, then connect the car, which should trip the GCFI until the fault is > corrected. Adding some very high value resistors between the "hot" leg of the > GFCI output and ground will increase it's sensitivity. This, by itself, might > be a trial and error project, and will require some number of resistors on > hand to experiment with. You will be careful when fiddling with this, right? > > Of course, you know where to look for common fault paths in the car? Motor > brush carbon dust, dried and cracked insulation on high voltage conductors, > intrusion of road splash and dust near energized conductors, etc? Any place > that pack voltage and 12 volts from the cars electrical system come together, > even come close at all, are highly suspect, metering, BMS, relays and > contactors, etc. If you start getting close to the problem(s), then a visit > to the motor shop's megger might be more informative. > > The ultimate solution might be to have a big, heavy isolation transformer > that you lug around everywhere. That was one of the good features of the old > Lester chargers, full isolation, and they made your car ride stylishly low, > no need for coil-overs... > > _______________________________________________ > UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub > ARCHIVE: http://www.evdl.org/archive/index.html > INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org > Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA) > _______________________________________________ UNSUBSCRIBE: http://www.evdl.org/help/index.html#usub ARCHIVE: http://www.evdl.org/archive/index.html INFO: http://lists.evdl.org/listinfo.cgi/ev-evdl.org Please discuss EV drag racing at NEDRA (http://groups.yahoo.com/group/NEDRA)
