Rotary phase adjustment size question

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>

  
Hi John, All, 

      I am in the process of constructing a SRSG with phase control using a 
1/7 HP motor, running in sync at 3600 RPM as verified by the modified RS 
Strobe light. The motor draws just under 2.4 Amps -at-120V. Since the motor is 
almost three times larger than in the example, I figure I'll need about 
120-150uF, I have 48 15uf 660V run caps, so no problem adding capacitance. 
However, my available unfried variacs are 2.5A, 20A and 30A. Also have a 10A 
with a dark brown dead section 1.25" wide about 2/3 of the way along. Can I 
use any of these variacs and should the fuse be larger? Since the variac is 
being used as a variable inductor rather than as a transformer, how critical 
is the current rating? I really don't have a feel for this and would rather 
not fry too small a variac, or mount a 26 lb monster where a 5 lb control 
will do. If I have to buy another one at 7-8amp then OK but I;d rather not 
unless necessary. 

Enlightenment please?? 

Matt D.