CAP's (again) (was Re: another transformer question

In reviewing the recent release of fluid from my cap, I am thinking
that maybe the aluminum cap may not be the best choice.

There was a post a month of so ago discussing the benefit of using
low ESR and another saying that multiple caps. 100uf and one small
unit.

Is there any special style that is bad, or best ?

Dave

--- In CAD_CAM_EDM_DRO@y..., "JJ" <jj5412@e...> wrote:
> For what it's worth, Jameco (www.jameco.com) has 470uf 100v caps for
> US$1.89.
>
> I know what I would do.
>
> Regards,
> JJ
>
> Be Kind, Be Careful, Be Yourself
>
>
>
> > -----Original Message-----
> > From: caudlet [mailto:tom@t...]
> > Sent: Sunday, August 11, 2002 1:24 PM
> > To: CAD_CAM_EDM_DRO@y...
> > Subject: [CAD_CAM_EDM_DRO] Re: another transformer question
> >
> >
> > <snip> for 48VDC so should just make it under 50V, but the
> > measurement says
> > > 60VDC, so should I risk it and go ahead to use the same
capacitor,
> > > even if only temporary? What happens when one exceed the rated
> > > voltage of a capacitor?
> > >
> > > Thanks
> > >
> > >
> >
> > In the short term normally nothing happens. If the overvoltage
lasts
> > too long or is way over the limit of the working voltage things
can
> > get interesting in a hurry. The insulation layer starts to break
> > down and the cap starts to draw excessive current which results
in a
> > rapid build up in internal heat and the electrolyte starts to
turn to
> > steam. Usually the result in larger caps is a hissing noise with
> > gook flowing out of the cap. The cap can explode (smaller ones
go
> > off like firecrackers) but the real danger is to down stream
> > components. If you loose the filter cap the electronics running
off
> > of it are essentially running off half wave AC at 120HZ...not
kind to
> > components expecting nice smooth DC!
> >
> > A lot of transformers are designed and rated at close to full
load to
> > account for losses in the windings and other magnetive things, so
a
> > 36VAC unit might go to 40VAC lightly loaded but 45Volts sounds
> > excessive. Your two 12VDC fans in series should really be
spinning
> > at 60VDC! The resistor in series will reduce that some but you
may
> > have to increase the value to keep the voltage across the fans
24VDC.
> >
> >
> >
> >
> > Addresses:
> > FAQ: http://www.ktmarketing.com/faq.html
> > FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> >
> > OFF Topic POSTS: General Machining
> > If you wish to post on unlimited OT subjects goto:
> > aol://5863:126/rec.crafts.metalworking or go thru Google.com
> > to reach it if you have trouble.
> > http://www.metalworking.com/news_servers.html
> >
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