Question about John Freau's phase adjustment circuit

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Original poster: "Coyle, Thomas M." <tcoyle@xxxxxxxxxxxxxxx>

Hi again. Thanks to everyone who responded to my polyurethane question.
I'm going to try baking the sucker per a couple folks' recommendations
and see how that goes. If all else fails, I'll just light it up and see
how it goes. I have plenty more acrylic and magnet wire laying around,
and winding the thing was indeed a zen experience.

Thanks also for the grounding advice - still thinking on the best way to
handle that one, some ways involving trying to convince my wife to let
me dig up a few feet of the front lawn...

Anyway, onto the next question: I just got a stock of variacs in, and I
wanted to build the phase controller. I have a question about the cap
value to use. According to the directions on John's site:

"To select the proper capacitor size, measure the voltage across the
motor and look for a 3 to 5 volt resonant voltage rise maximum at some
point in the variac's range."

Maybe I'm missing something - how will that help me to determine the
value of the cap?

It turns out that I'm using the exact same teletype motor that John's
using in that page, and this line leads me to believe that the 47uF,
240VAC cap would be fine:

"This controller is for the new sync gap below, but it will work for
other sync motors too."

Thanks again!

Tom