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Old 04-07-2011, 01:15 PM   #4606 (permalink)
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Originally Posted by DJBecker View Post
That configuration wouldn't be balanced.

The layout should be based around equal path length. The current shouldn't have an easier path to some devices.

This requires that the motor connect to opposite ends of the controller. Otherwise the freewheel current will mostly prefer the "close" diode. When that burns out because it's carrying all of the current, the current will prefer the next device and burn that out in turn.
Just an FYI, but I've passed 7k miles (in most likely the harshest temperature environment) with this controller and have all 3 bus bars coming out the same end (wouldn't fit otherwise). This could indicate a few things:

-the current may have an easier path through some components, but it's not significant enough to have an effect
-the heat spreader performs adequately enough to distribute the heat and keep the diodes from entering thermal runaway
-there's not enough time on the controller for any problems related to this to surface

I guess we can try to quantify this effect with a model, but I'm not up for it at the moment... I suspect it's ok.
ReVolt AZ testing thread:
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