Alt-BEAM Archive
Message #02108
To: beam@corp.sgi.com
From: Jacob Booth J.Booth@mackillop.acu.edu.au
Date: Thu, 8 Apr 1999 00:58:46 -0700 (PDT)
Subject: [alt-beam] Re: capacitors exploding
>Date: Thu, 08 Apr 1999 18:01:55
>To: Benjamin Edward Hitchcock
>From: Jacob Booth
>Subject: Re: capacitors exploding
>
>At 07:43 8/04/99 +1000, you wrote:
>>
>>
>>Reading about how capacitors explode reminded me of something I saw at
>>work a couple of months ago.
>>
>>We get all manner of devices in to our workshop to be repaired, and we
>>have all manner of people repairing the said devices.
>>
>>Well, this was the worst combination - a tricky job, carried out by our
>>least talented tradesman. Anyway, to cut a long story short, he hooked up
>>a 200 uF, 400V cap backwards onto a 300 volt DC supply.
>>
>>He was very glad that he wasn't standing directly over it when he switched
>>the power on - he only received a spattering of electrolyte. But the roof
>>of our workshop wasn't so lucky. There were bits of yellow paper and tin
>>foil all over the place, and some of it was embedded in the roof. And,
>>there was the loudest bang I have heard for a long time.
>>
>
>I was building a large audio amplifier, and one of the HUGE electros was
put in the wrong way across the 50v rail. (HUGE meaning one in a can that
has a bracket attached to the chassis). Power up, and I saw it bulge. Scared
the life out of me when it blew out a tiny hole, then sprayed a huge cloud
of electrolyte into the room. Fastest dive and cord pull I have ever
performed. At least I only needed to replace the elctro, not an eyeball or
half a face.
>
>As an aside, caps do not need to be huge or of a large value to be
'interesting performers'... A power isolation cap 'pop remover' (mains rated
'self healing' type) in the same amp failed. These are supposed to 'heal' if
a short occurs internally (that is one of the reasons thay are mains rated).
This one didn't, and sent out the same amount of electro as the big
electrolytic, as well as crack open with a fair bit of force.
>
>Need I say that final testing was done with me at the wall switch quite a
distance away :)
>
>Oh, and the amp is still working with no problems after five years now!
>
> Regards,
> Jaocb
>
-----------------------------
j.booth@mackillop.acu.edu.au
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