From: Paul
Date: Thu, 12 Sep 2002 11:00:37 +0100
Subject: Re: [TSSP] Top Voltage
I modeled the coil details to get:
With toroid: 37.752 kHz
With toroid + rod: 37.479 kHz
With toroid + rod + 1.833 sphere: 37.138 kHz
I'm not sure whether rod and sphere were in place when you pinged
with toroid. Assuming they were, we get
Measured Modelled Error
f1: 37.801 kHz 37.138 kHz -1.7%
f3: 113.550 kHz 113.929 kHz +0.3%
f5: 171.773 kHz 174.632 kHz +1.7%
so perhaps rod and sphere weren't in place?
Specific surface field gradient is highest on the sphere,
at 0.300 kV/cm/kV for the largest sphere, thus breakout would
be at a topvolts of 26/0.3 = 87 kV topvolts. The smallest sphere
gives 0.479 kV/cm/kV to give a breakout at 26/0.479 = 54kV.
These can be referred to the base current and primary voltage,
Vtop Ibase Vpri
(peak) (peak) (peak)
Small sphere: 54kV 0.6 amps 80 V
Large sphere: 87kV 0.9 amps 130 V
So by my reckoning, all three spheres should have been breaking out
comfortably with the base currents shown in S1-S3.gif.
--
Paul Nicholson,
--
Maintainer Paul Nicholson, paul@abelian.demon.co.uk.