[ARC5] Radio Shack transformers - was:Vibrator Power Supplies

[Bill Cromwell]

Hi,

I ran mine overnight on my BC-453 watching for some of the experimental
stations on 600 meters. That RS transformer only powers the tube
heaters.  It wasn't over heated but was running a shade less than a
quarter of it's "rated" load. It was warm enough I wouldn't want to load
it any further. A separate transformer provides B+. That other
transformer has an unused heater winding and was actually *cold* to the
touch. The garage is allowed to cool into the upper 50s overnight in the
Michigan winter. I'm glad this was pointed out. Now to start sprinkling
some bucking transformers around.

73,

Bill  KU8H




On Sun, 2012-12-09 at 15:39 -0800, J. Forster wrote:
> I just measured the core loss of a Radio Shack 12.6V @ 2A transformer. The
> unit is low loss to about 115 VAC, then rises rapidly:
> 
> VAC      Power
> 
> 090       2
> 100       2
> 110       3
> 120       4
> 130       6
> 138       8
> 
> The instrument was a Sencore PR570 which analog multiplies V & I, so it's
> real power, not reactive. This is virtually all core loss. Since the
> transformer is unloaded, the copper losses are small.
> 
> -John