Re: [CAD_CAM_EDM_DRO] Re: another transformer question

Peter,

Capacitors should not be run over their rated value. You also have a peak
value. I have never had a capacitor to blow up, but they can.

Check you readings again and verify the voltage. Also check your line
voltage.

Bob Campbell

----- Original Message -----
From: "eforum3001" <eforum@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, August 10, 2002 11:24 AM
Subject: [CAD_CAM_EDM_DRO] Re: another transformer question


> Hi,
>
> Darn. Another poser to puzzle over. Now that the DC is OK, I have
> started to connect the Geckos to the power supply, and just noticed
> that the capacitors are only rated 50V. The power supply was designed
> 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
>
> Peter
>
> --- In CAD_CAM_EDM_DRO@y..., "eforum3001" <eforum@s...> wrote:
> > "Robert Campbell" <bob@c...> wrote:
> >
> > > What AC voltage do you read at the input to the bridge
> rectifier?
> > I may
> > > only be 18 volts AC.
> >
> > > Does the transformer output have four leads?
> >
> > Hi Bob,
> >
> > Input at bridge rectifier (=output at secondary) was 45VAC (It was
> > suppose to be 36VAC but looks like our "ENRON" isn't controlling
> the
> > voltage that well.
> >
> > On reading your message, I powered up the power supply again, and
> > this time I got 60VDC. So beyound the over-voltage, everything is
> > working as it should. I don't understand whay when I first measured
> > it, the output was so low. I am pretty sure I got 25VDC because the
> > measurement was repeated a few times. Perhaps it's because it is
> new,
> > perhaps bridge rectifier can be "sticky" when new? and have to be
> > broken in.
> >
> > Thanks
> >
> > Peter
> >
> >
> >
> >
> >
> > > From: "eforum3001" <eforum@s...>
> > > To: <CAD_CAM_EDM_DRO@y...>
> > > Sent: Saturday, August 10, 2002 10:17 AM
> > > Subject: [CAD_CAM_EDM_DRO] another transformer question
> > >
> > >
> > > > Hi,
> > > >
> > > > This is another transformer question. Seeing that the Gecko
> likes
> > > > high voltage, I am now in the process of upgrading the power
> > supply,
> > > > changing the 24VAC transformer to a 36VAC transformer.
> > > >
> > > > So, with a 36VAC secondary, a bridge-rectifier plus capacitor, I
> > > > should get about 48VDC, right?
> > > >
> > > > Wrong! I got only 25VDC!
> > > >
> > > > Only thing is, I am using the output from the bridge rectifier
> to
> > > > drive 2 (two) 12V 1.8A fans in series plus a 150ohm 5W
> resistor.
> > I am
> > > > doing this so that the fans can act as a blled resistor.
> > > >
> > > > Why can't I get 48VDC with this set-up?
> > > >
> > > > Thanks
> > > >
> > > > Peter
> > > >
> > > >
> > > > Addresses:
> > > > FAQ: http://www.ktmarketing.com/faq.html
> > > > FILES: http://groups.yahoo.com/group/CAD_CAM_EDM_DRO/files/
> > > >
> > > > OFF Topic POSTS: General Machining
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> > reach it if
> > > you have trouble.
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> > > >
> > > > http://groups.yahoo.com/group/jobshophomeshop I consider this
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>
> 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
>
> http://groups.yahoo.com/group/jobshophomeshop I consider this as a
sister site to the CCED group, as many of the same members are there, for OT
subjects, that are not allowed on the CCED list.
>
> NOTICE: ALL POSTINGS TO THIS GROUP BECOME PUBLIC DOMAIN BY POSTING THEM.
DON'T POST IF YOU CAN NOT ACCEPT THIS.....NO EXCEPTIONS........
>
> Post messages: CAD_CAM_EDM_DRO@yahoogroups.com
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> List Owner
>
>
>
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>