On Fri, 30 Nov 2012 00:18:28 -0800 (PST), put
finger to keyboard and composed:

"The second IGBT's body diode allows the coil current to decay
gracefully when the first IGBT switches off."

No. Don't you understand that ground is a human thing, not an electronic thing ? There is no up and down.

The only possible difference is if one side of the coil has more capacitance to ground, which would make an inbalance. This COULD happen, but if it did, the bottom Xsistr failing would be such a common failure mode it would be on Fox ****ing news. Switching the leads to the inductor could prove it, because then the top Xsistr would fail first.

We are talking about a ground fault condition here, without that, no anomality in the load could be imbalanced after it is running. Failing on startup is a different story, and this ain't it.

Get a grip, or a firm base of theory. Somehting. I'm surprised people can tie their shoes,,,, oh wait, they can't.

So much for that.

I don't understand what triggered your "ground" rant. Of course the
circuit is balanced, and of course there is no connection to terra
firma. Did I suggest anything else?

Are you perhaps misunderstanding what I meant by "second" and "first"?
All I'm saying is that after the first IGBT turns off, the second
IGBT's flyback diode allows the coil current to decay. Then the second
IGBT turns on. After the second IGBT turns off, then the first IGBT's
diode allows the coil current to decay, and so on.

- Franc Zabkar
--
Please remove one 'i' from my address when replying by email.