[Boatanchors] Xfmr temperature?

[Ron]

Hi John.

I chopped off thr HV windings, removed the magnetic shunt  and wound 
sufficient secondary  turns to power the filaments of a 4-1000 /3-1000Z.
What I find is that the primary seems to be wound for about 90 VAC .
Higher primary voltages would saturate the core and it would self heat,
On regular transformers , they don't run the core that close to 
saturation so dropping it to 60 VAC and adjusting the secondary is OK .
I use a Vaiac or Powerstat to do that job  but a big adjustable resistor 
works well also.


Your idea is a good one but some have little room to add enough turns.

My read was that the line would sag under power for it's original use 
powering the microwave .
---
Ron

msix@nmia.com wrote:

>Testing several microwave xfmrs for an HV supply
>showed the idling core temp stabilizes around 175F.
>
>Adding 4 turns to the primary lowered it to 140F.
>
>Wonder if others have seen the same thing?
>73 John W7ZFB
>
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