Re: What part of "unsupported"....

mroberds@xxxxxxxxxxxxxxxx writes:
Graham Reed <greed@xxxxxxxxx> wrote:
mroberds@xxxxxxxxxxxxxxxx writes:

The programmer with a screwdriver in me thinks, "Get a Variac and
shoot it 130 V or 140 V for a while. See if that fixes it."

My first thought was "dropping the voltage won't help". Then I
remembered that in some benighted places 130V is _up_ from mains.

The EE in me with a screwdriver and no Variac around the house

For raising the line voltage, wire up a regular 120:X (X<120)
transformer in boost, or wire the "secondaries" of a 120:12.6 and
120:6.3 transformer together

and saturate the core of the second one when you give it twice the mmf
it was designed for. Of course, with fairly high resistance
secondaries giving a big no-load to full-load drop there may be more
turns on that 6.3 winding, and it may have been designed around lower
flux densities than I was pushing through our teeny tiny toroidals, lo
these N years back, so you may get away with it.

Better to wire the primary and secondary together as an
autotransformer, and everything works out nicely.

Geez, I got like a B or a C in EE 101

I would snarkily say "it shows", but Electromagnetic Machines was a
second year subject in my EE course and even then this was glossed
over somewhat - it wasn't until I started designing transformers for
pay a decade later that "core saturation" and "excitation current"
meant anything.

mlp
.

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