[Amps] Paralleling plate xfmrs.

[jim.thom jim.thom@telus.net]

Date: Mon, 27 Oct 2025 17:53:01 -0700
From: Michael Tope <W4EF at dellroy.com>
To: amps at contesting.com
Subject: Re: [Amps] Paralleling plate xfmrs.

Hi Jim,



>Do you know the primary winding resistance of the subject transformers?

>73, Mike W4EF................

No clue.  I don't think Scott has a lab supply with enough current to do
the job.
Right now, the primary's are wired in parallel, using the 250 vac taps for
initial testing.

On a similar note,  I got email from folks who used to work for companies
that wound xfmrs.  They all  pointed out that  TURNS  counters are used to
count both primary...and sec turns....so each transformer ends up
identical.

One other thing, 7.5 vac @  50 amp fil xfmrs  (for a 3x3 tube)   have been
paralleled to make a 7.5 vac @ 100 amp fil  xfmr.....used for a 3x10 tube.
Zero issues there.   Henry Radio did just that on their 3x10 amps.   It's
common practise on hb  3x10 amps.  The bigger  3x15/20 tubes require a 6.3
vac  @ 160 amp fil xfmr.

Jim   VE7RF