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Old 10-23-2009, 09:06 PM   #10 (permalink)
bwilson4web
Engineering first
 
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Join Date: Mar 2009
Location: Huntsville, AL
Posts: 843

17 i3-REx - '14 BMW i3-REx
Last 3: 45.67 mpg (US)

Blue Bob's - '19 Tesla Std Rng Plus
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Quote:
Originally Posted by orange4boy View Post
. . .
Have they figured out what makes them short out? . . .
That remains an open question. I found one Japanese paper about voids in the potting compound and high dV/dt leading to coronal discharges in the voids. But the problem is once the internal short starts, it pretty well wipes out the initial fault ... for folks with ordinary means.
Quote:
Originally Posted by orange4boy View Post
. . .Electric motors are notoriously robust, their main enemy being heat. In an oil bath I suppose debris might also pose a hazard.
I've seen some pretty rank oil samples and suspect two things:
  1. manufacturing debris - my 5k transaxle oil change showed a small amount of metal shavings. Leave them in for 60k miles and who knows what damage they might do.
  2. micro-dieseling - admitted a long shot, I suspect high-speeds lead to micro-dieseling and accumulation of combustion by-products in the oil. These are conductive.
Quote:
Originally Posted by orange4boy View Post
. . .Is there a fluid cooler on these? Who winds them? I'm guessing it's Nippon Denso.
No idea of who makes them but there is no fluid cooler and my temperature measurements indicate none is needed.
Quote:
Originally Posted by orange4boy View Post
. . .I found some OEM shop manuals on ebay. I guess I should get the 2003. They seem to be about $130-150 a set.
That seems to be the going rate for used manuals. I bought mine new for double that.

Bob Wilson
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2019 Tesla Model 3 Std. Range Plus - 215 mi EV
2017 BMW i3-REx - 106 mi EV, 88 mi mid-grade
Retired engineer, Huntsville, AL
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