On 1/9/2013 6:49 AM, Danpatgal wrote:
It's probably a simple and too often occurrence, but on my way to work
yesterday morning I heard a loud POP! I was accelerating, but not up a big
hill or anything ... I might have been pulling 100 amps is all (in my 120v /
2000 lb Lectric Leopard) and it was maybe mile 2 in my commute on a cold
morning, so it wasn't overheating. I was able to keep going (which I found
miraculous), turned around, went home and humbly scraped off the frost from
my gas car and went to work.
Today I was able to look more closely and saw the end cap to my Curtis
1221C-7401 laying next to some additional spray - so clearly it had
exploded.
1.- What most likely exploded?
2.- How is it that after such an event the controller kept going?
3.- Can I keep driving it, or is it now even more likely it will fail
totally and leave me stranded?
4.- Is there a possible cause other than just old age that I should be
looking into to correct?
5.- Is it repairable ... or should I use this event as a not-so-subtle hint
to upgrade the controller?
Hi Dan,
You are probably way low on your 2000 lbs. weight estimate. My Leopard
weighed more like 2500 lbs with twelve 12v batteries. The Curtis 1221 is
a rather wimpy controller for that weight of a vehicle, so it will be
working hard.
I assume you mean 100 battery amps? If you were in a high gear so motor
RPM was low, then motor current would have been much higher. Motor
current is the controller killer. Don't shift it like an ICE (motor RPM
low); electric motors and controllers work better at high RPM.
I think you mentioned that you also have the original fiberboard adapter
plate and setscrew motor coupler? These parts are not good for high
torque; that's another reason to avoid high-torque low-speed operation.
Sniff around the controller and see what you smell. Also look inside for
any loose pieces.
- If it was very cold, and you just took it off charge (pack at
its maximum voltage), and you are running your Curtis at its
maximum rated voltage (like 120v on a 72-120v controller),
then it could be that one of the big electrolytic capacitors
exploded. They have a strong alkaline smell, somewhat like
oven cleaner.
- If the failure occurred at high motor current, and there is
no noticeable smell, and you find black bits of plastic
rattling around inside, then one of your MOSFET transistors
shorted and exploded.
In either case, the controller can still work; but is damaged. The load
will shift to the remaining parts, which will be under greater stress,
so they are more likely to fail soon as well. If you expect to fix the
controller, DO IT NOW while the damage is minimal! If you wait until it
fails completely, it's a lot more difficult and expensive to repair.
--
*BE* the change that you wish to see in the world. -- Mahatma Gandhi
--
Lee A. Hart, http://www.sunrise-ev.com/LeesEVs.htm
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