Quote:
Originally Posted by jyanof
In both graphs you posted, and all 3 events shown in the graphs, the same thing happens:
1 - motor current tracks the command current at first: notice the blue and red lines are on top of each other at first.
2 - then, motor current falls and matches the battery current (light blue line). also, the pwm line (pink) jumps to 512 which is wide open. these all agree with each other - when the mosfets are full on, the motor current and battery current will be the same
this is very odd behavior, especially considering that the vehicle slows down. in normal driving, you will likely never reach wide open pwm, and if you do, it's at a high speed and high current.
i'd say your controller is working correctly, but something is wrong on the motor end. the controller is outputting power, but it's not going to the motor.
I think you mentioned your battery voltage is something like 120v and the charts show that they're pushing about 100 amps when the event happens, so that's 12 kW that's just going into heat somewhere!
it really sounds like a motor problem, maybe something is shorting the field or rotor winding so you're only energizing one set of windings? or, a loose connection? maybe it's fine at first, but as the motor heats up, things expand and cause something to short out? or, maybe it's speed related?
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J-
thanks for the reply. I see what you are saying, and understand that the KW must be going somewhere and turning into heat or something. I watched my ammeter continue to rise after the bus stopped accelerating, so that made me think that the juice was still flowing into something.
Loose connections are easy to check, but "shorting the field" and "rotor windings" are not things I'm familiar with. Can someone point me in the direction of how to check these things? And again, this all happened overnight. Everything was running FINE the night before and the next day this just happened. Is the field or windings things that can go bad with no warning?
Thanks for all your help.
