[Amps] Note on paralelling transformers

[Larry Carman]

William,
I could have sworn that the part #s were the same on
the HV PS transformers I pulled from the 2k and 3k D Henrys. Maybe
there were some alterations in the unit/s at some point along the way.
Does anyone know of a website I can reference the specs on the
transformers that I pulled from these Hernry RF gens???

Larry N5BIP


----- Original Message ----- 
From: "Dr. William J. Schmidt, II" <bill at wjschmidt.com>
To: "Larry Carman" <lncarman at swbell.net>
Sent: Tuesday, May 25, 2004 8:41 PM
Subject: Re: [Amps] Note on paralelling transformers


> Larry...
>
> Nope!!!!!  the 2 and the 3kW use different transformers... and by
themselves
> individually don't make enough voltage to run most big tubes.  That
3CX5000
> of yours just starts to bark at 6kV.  The 3300 volts in the henry heaters
is
> barely enough to make those tubes work too.
>
> Sincerely,
>
> Dr. William J. Schmidt, II  K9HZ
> Trustee of the North American QRO - Central Division Club - K9ZC
>
> "Collector of Edison Wind-up Phonographs... Do you have one for me?"
> Email: bill at wjschmidt.com
> Alternate Email: wmschmidt at charter.net
> WebPage: www.wjschmidt.com
>
>
>
> ----- Original Message ----- 
> From: "Larry Carman" <lncarman at swbell.net>
> To: <amps at contesting.com>
> Sent: Tuesday, May 25, 2004 10:05 AM
> Subject: Re: [Amps] Note on paralelling transformers
>
>
> > My last amp project ( 3cpx5000a7 ) required a pretty hefty PS. I used a
> > couple of the transformers that were pulls from the Henry RF gens
running
> > the 3cx3000a7 tube. On the secondary of each transformer I used full
wave
> HV
> > diode modules, combining the rectified dc HV from each into a common B+
> > using only one oil capacitor at 24 mf. Seems to work pretty good.
> > Bill, aren't the power transformers used in the Henry 2000 and Henry
3000
> RF
> > gens the same? I don't know what the ratings are for them but, judging
> from
> > the weight, I believe a single transformer would easly handle 4 KW PEP
> out.
> >
> > Larry N5BIP
> >
> > ----- Original Message ----- 
> > From: "Bill L. Fuqua" <wlfuqu00 at uky.edu>
> > To: <craxd1 at ezwv.com>
> > Cc: <amps at contesting.com>
> > Sent: Saturday, May 22, 2004 6:31 PM
> > Subject: Re: [Amps] Note on paralelling transformers
> >
> >
> >
> > I have a 5KW Henry Radio RF generator (20 meter transmitter?) in the
> garage.
> > It has two plate supply transformers in parallel. The 3KW version only
has
> > one o f these transformers.
> >
> > To check secondarys put them in series and measure the voltage output.
If
> it
> > is high reverse the connections if  it is not make sure that the low
> voltage
> > that you measure divided by the transformers secondary resistance is
very
> > small compared to the current rating for the transformers.
> >
> > 73
> > Bill wa4lav
> >
> > -----Original Message-----
> > From: Will Matney <craxd1 at ezwv.com>
> > To: "amps at contesting.com" <amps at contesting.com>
> > Date: Fri, 21 May 2004 12:43:37 -0400
> > Subject: [Amps] Note on paralelling transformers
> >
> > I figured I might as well add this because home brew amps have used
> > paralleled transformer in the past to either increase the voltage or the
> > current. When connecting the transformer windings, they must be "in
> > phase" with each other. Some transformers is hard to connect this way
> > because the have two of the same color wires for each winding. If the
> > transformers are connected "out of phase" they will buck each other.
> > When this happens, you would get little or no output voltage and they
> > would act like they were shorted. You will know when this happens
> > believe me. You'll get a BIG hum and the fuse will open. Hopefully it
> > wont damage the windings too! When winding transformers or ordering
> > them, always have a different color wire for the start and stop of each
> > winding. This way it is easy to keep them in phase with on another. On
> > the schematics you'll see a black dot at one leg of each winding. This
> > is put there so you will know the correct connection to keep it in
> > phase. On transformers with the same color leads like two black wires
> > for the primary, you will need to find which goes to the start and stop
> > of each winding. For parallel operation the two starts tie together and
> > the two stops. In series operation, you will have a start and stop
> > together with the other two going to the line. Anyhow, I've wrote about
> > all I can think of on this so have at it!
> >
> > Will Matney
> > US Amp
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> >
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