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Coil Efficiency
From: Malcolm Watts[SMTP:MALCOLM-at-directorate.wnp.ac.nz]
Sent: Sunday, July 27, 1997 2:55 PM
To: tesla-at-pupman-dot-com
Subject: Coil Efficiency
Hi all,
It should be plain from the operational scenario I outlined
earlier that TC efficiency is going to vay considerably depending on
its loading conditions. You can see the effects of this in the gap
discharge under different secondary loading conditions. Max efficiency
in terms of throughput is being obtained when the gap reaches minimum
brightness. In the coupled system this is the point at which Qsec has
dropped to allow coupling to become critical. From the primary's
point of view, the resistance reflected into it has become equal to
its own internal resistance. Since most of the resistance in the
primary circuit is a non-linear gap resistance, it is clear that a
non-linear load is required for this condition to be met (i.e. spark).
Resistance reflected into the primary is dependent on k and
Qloaded for the secondary. That being so, finding the optimum k for
the power the coil is running at is required to obtain best output
(and efficiency). To throw a fly into the ointment, you can achieve
the same loading conditions at different attached spark lengths. If
in doubt, get a good oscilloscope and capture the waveforms of a
normally running secondary.
Another two cents,
Malcolm