Hi Barry, Tnx for your answer.
I'm positive. I disconnected the cap from the xformer and measured it. It is a
hefty thing, measures about 3x4x1 inches. No polarity. Most probably an
oil-filled paper capacitor.
73 de Angel Vilaseca HB9SLV
Barry Kirkwood wrote:
> Angel:
> Are you sure it is 10mfd?
> Sometimes smaller capacitors are put across power transformer windings to
> subdue voltage spikes coming down the line.
> Normally a small resistance is in series with the capacitor to reduce
> resonance, but in some cases the dc resistance of the winding is sufficient.
> 73
> barry
>
> end
> Barry Kirkwood PhD ZL1DD
> Signal Hill Homestay
> 66 Cory Road
> Palm Beach
> Waiheke Island 1240
> NEW ZEALAND
> ph/fax 64-9-372-5161
> www.waiheke.co.nz/signal.htm
> ----- Original Message -----
> From: "Angel Vilaseca" <avilaseca@bluewin.ch>
> To: "AMPS" <amps@contesting.com>
> Sent: Tuesday, May 18, 2004 8:38 AM
> Subject: [Amps] Tuned power transformer
>
> > Hi,
> >
> > I am taking apart an old HV power supply made in the late '40s, probably
> > in Germany. From its size, the power transformer should be rated for
> > approximately 1 KW. It has an HV secondary winding 800-0-800 Volts and
> > two 12 V for filaments. It has a vacuum rectifier.
> >
> > It has tuned chokes and I also found that a 10 uF cap is wired across
> > the primary winding of the power transformer.
> >
> > So I guess that this must be a tuned-primary power trnsformer. I never
> > saw this before. How does this work? What are the properties of a
> > tuned-primary power transformer? Does it prevent current inrush at
> > power-on like a tuned choke?
> >
> > Of course, I will replace the vacuum rectifier with solid-state diodes.
> > Should I leave the 10 uF cap acros ethe primary or remove it?
> >
> > Angel Vilaseca HB9SLV
> >
> >
> >
> >
> > _______________________________________________
> > Amps mailing list
> > Amps@contesting.com
> > http://lists.contesting.com/mailman/listinfo/amps
> >
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