[Prev][Next][Index][Thread]
Winding vs Space-Charge Capacitance
From: terryf-at-verinet-dot-com[SMTP:terryf-at-verinet-dot-com]
Sent: Saturday, November 01, 1997 4:44 PM
To: tesla-at-pupman-dot-com
Subject: Winding vs Space-Charge Capacitance
Hi all,
Testing I have done on secondary coils with no top toroid suggests that
the secondary inductor's capacitance is composed of two main capacitances in
parallel. The first capacitance is internal to the coil winding itself and
is probably composed of turn-to-turn capacitance. The second capacitance is
a large space-charge region that is developed around the top end of the
coil. The first capacitance is in the order of 0.25 pF while the second
capacitance is on the order of 6.3 pF.
Coil length 29.0 inches
Diameter 4.25 inches
1000 turns #30 wire
Non-Linear (winding pitch proportional to cos(x))
inductance 16.06 mH
Fo 496.2 KHz (no top terminal)
Rac ~108 ohms
Q ~460
Note: Rac and Q may be inaccurate (unproven test methods).
If this is true than it would suggest a number of possibilities to optimize
output voltage. I am surprised that the turn-to-turn capacitance is so low.
This is one of my non-linear wound coils but if the turn-to-turn capacitance
is this low, I should be concentrating on field patterns and forget the
internal capacitances. I haven't cross-checked these results so I may have
a measurement problem or something.
Does anyone have any comments on these results or comments on the
small turn-to-turn capacitances I seem to be seeing.
Thanks
Terry
terryf-at-verinet-dot-com