Twin coils 180 degrees out of phase : Weird happennings

From:  ESchulz531-at-aol-dot-com [SMTP:ESchulz531-at-aol-dot-com]
Sent:  Friday, July 03, 1998 6:45 PM
To:  tesla-at-pupman-dot-com
Subject:  Twin coils 180 degrees out of phase :  Weird happennings

	I made two identical secondary.  Same inductance 20 mh, 
only 0.2% off.  But my toriods are different.  One is 5" aluminum 
duct about 17 pf and the other is 7" about 22 pf.  The primaries 
are connected in series.  Same inductance in each.  Using 
Medhurst formula I get a self capacitance of 11 pf.  So the additive 
capacitance would be 28 pf and 33 pf.  So the frequency for each 
coil should be 213 kHz and 196 kHz.  With the coils alone I 
measured them to be 216 kHz and 198 kHz.

OK that's all great.  Now's the weird part

Now with the coils together I measured a 176 kHz frequency on 
the 7" and 353 kHz on the 5".  ?  What in the world?  By the way 
176 * 2 = 352.  I couldn't find any second harmonic on the 7" but 
I found a 2,3,4 harmonics on the 5".  The voltage on the 5" was 3 
times greater than on the 7"

I measured the frequency with my o-scope and a RF generator.  
The primaries in series and no primary cap.  Normally my scope 
only loads my coils by about 0.7% By load I mean change the 

I imagine everything will go back to normal when I get identical 
toriods but what's going on here?


Erik / Gradient