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
> > >
> > >
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