[Hallicrafters] Lets hash it over one more time.

[GBrown]

I know the topic of power trannys and primary voltages have been hashed over
many a times but thought I would just jump in with another perspective that
I don't think crossed to many minds.
    Lets start with ahhhhhhhhhhhhh, an SX-28A power tranny, or any power
tranny that fits the approx. voltages I am about to use.
Lets use 115 volts AC. as a starting point for primary side of transformer.
Now, lets say there is 230 turns of wire on the primary. This will give us
.5 VPT (volts per turn).
This transformer will give us the following.
.478 VPT @ 110 VAC
.500 VPT @ 115 VAC
.521 VPT @ 120 VAC
.543 VPT @ 125 VAC.
    Now, lets just say we have a secondary voltage of 600 volts. I know
BORINGGGGGGGGGG but just hang in there.
That's 1200 turns. OK, now lets do some math.....
.478 VPT X 1200 turns = 573.6 volts
.500 VPT X 1200 turns = 600.0 volts
.521 VPT X 1200 turns = 625.2 volts
.543 VPT X 1200 turns = 651.6 volts
This gives us a difference of 78 volts between 110 volts and 125 volts on
the primary. REMEMBER, turns remain the same. That's about a 12% difference
    Now, what about filament voltages
12% of 6.3 volts is .756 volts. 6.3 + .756 = 7.056 volts
12% of 5.0 volts is .600 volts. 5.0 + .600 = 5.600 volts.
What I am trying to get across is, do you want your filaments running almost
another volt higher than normal? I don't. 6146's and other tubes are getting
to expensive to replace, not even taking into consideration other factors
that are working close to factory voltages. A 400 volt capacitor working at
480 volts. This is just a for instance.
    Toaster ovens work great to get rid of moisture but I cook my trannys at
225 degrees. I also, while still hot, dip them into a varnish and let hang
to dry. This will help "lock" the windings onto the laminations and will
also help seal any moisture from getting back in. If the tranny fails
because of the 225 degree baking temp. It was bound to fail anyway, no
matter what you did, short of rewinding.
    If I can answer any other questions about trannys, just shoot me an
email.
    Hope this little "soap box outburst" has helped a few.

Regards,
Gary...WZ1M