{Collins} Re: Heath Power supply: "NO" to parallel XFMRs





>From: "Charlie" <pincon@xxxxxxxxx>
>Reply-To: pincon@xxxxxxxxx
>To: <collins@xxxxxxxxxxxxx>
>Subject: {Collins}  Heath Power supply:  "NO" to parallel XFMRs
>Date: Wed, 9 Aug 2006 07:49:33 -0400
>
>As to the Heath/KWM-2 power supply question:
>
>I would advise against adding a transformer in parallel because unless the
>outputs are EXACTLY matched, you'll end up with high circulating currents
>and excess heat.   It works OK for AC inputs, but don't do it for the
>secondary.  THAT's why I recommend the serial connection of a 12 V xmfr (24
>VAC filaments) because it avoids that problem.
>

The only time paralleling transformer windings works-outside the power 
distribution industry where they do have very precise matching of windings, 
easier when the windings are in fact heavy copper bus bar-is on a single 
transformer with multifilar windings specifically designed for series or 
parallel connection.

I'd rather just use a whole separate filament transformer. There are some 
very reasonably priced toroids out there and there is room in the case, if 
memory serves.


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