RE: The MMC debate continues . . . . . .

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "S&JY" <youngs@xxxxxxxxx>

I agree with Bart.  But I recommend going one step further.  That is, don't
trust your bleeders - they can fail open, although rarely if not abused.
It's best to short all caps before handling them.  Alternately, for DC
systems with voltage monitoring, you can watch the voltage across a MMC with
bleeders fall to zero and safely handle the caps.  If any bleed resistor was
open, the DC voltage would not reduce to zero, except very slowly by the
load of the meter itself.

--Steve Y.

-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Monday, February 19, 2007 5:13 PM
To: tesla@xxxxxxxxxx
Subject: Re: The MMC debate continues . . . . . .

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Well, I just had to weigh in on this one.

AC or DC, bad experience or not, it doesn't matter. In the event the
load is disconnected due to a failure or whatever at the wrong time,
it is possible to sustain a substantial charge on the cap or cap bank
(MMC included). I did have a situation and got a nasty bite! It
hurts! I remember how angry I was with myself because I knew I should
have installed bleeders. But, I had previously run so long without
even a sneeze that I simply didn't bother myself with it. After the
incident, I do. Funny how one can change their views so quickly.

Bleeders (or other discharge schemes) are no different than green
wire safety ground. It's there to prevent injury in the event
something unforeseen occurs. People will choose to do cap discharging
a number of ways; I prefer bleeders and I also doublecheck with a
shorting bar (all coils, little or big).

Take care,
Bart