PFC on MOT Pair

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

Original poster: "Matthew Smith by way of Terry Fritz <twftesla-at-qwest-dot-net>" <matt-at-kbc-dot-net.au>

Hi All

College was a long time ago and I can't remember how to work this out - 
anyone help?

Two MOTs - primaries in parallel, secondaries in series; they are rated 
for 240V input and both have approximate turns ratio of 1:7.95, each 
giving approximately 1.9kV.

Mains frequency is 50Hz.

I have determined the primary restistances to be 2.7 and 3.0 Ohms and 
the secondary resistances 85 and 109 Ohms respectively.  These figures 
were measured using a Wavetek 27XT and confirmed using decade resistance 
+ Wheatstone Bridge of a "traditional" Megger tester.  (The inductance 
didn't half make the needle vibrate at low cranking speeds - like trying 
to measure AC with a DC voltmeter.)  I attempted to measure inductance 
using the Wavetek, but it was either two low or too high to register.  I 
have yet to check primary current since I currently lack a CT and don't 
like using DMMs directly for current measurement! (I've had one fry before.)

I guess that is not enough data to calculate the value of a PFC 
capacitor but I would like to know

a) is there a rule of thumb value for capacitor sizes for an array like 
this?
b) what is the actual formula that I should be using, if I had the 
inductance figures (which is what I guess that I'm missing)?

Cheers

Matthew Smith