That's the thing that's bugging me... Even though I have the motor in many pieces, there isn't an obvious neutral connection. As far as I know (from looking at analyses of similar motor by the DOE, the motor is wired wye, not delta. I just can't find the magic center point.
Acually, I'll test to see if there is any conductivity between any phase and the case. That would be interesting.
I did have an electric car conversion book that was very specific that the battery, controller, and motor needed to be isolated from the chassis. You shouldn't use the chassis as "ground."
- Just the experience of building my solar system...
- E*clipse
Quote:
Originally Posted by thingstodo
Most (perhaps all) commercial and industrial induction motors have the frame as a ground point. A High Resistance Ground resistor is connected to the frame or ground on the power transormer, which goes to ground for the building, or ground grid. Measuring the voltage across the ground resistor detects a failure in one of your motors, where one phase has worn through the insulation and has put dangerous voltage on the frame of the motor.
I've been struggling with what to do on a vehicle. It's tough to isolate ALL of the metal on a motor from the car frame. But if you are getting into 300 or 600VDC for a pack, just leaning on the car and touching the motor (or controller, or whatever the worn-through wire is touching) is going to give you a NASTY poke, perhaps a 'you're dead' shock.
There are BMS's that claim to monitor this. I have no experience with them. They'd have to convince me that they know what they are doing.
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