Re: coil losses
Subject: Re: coil losses
From: Terry Fritz <twftesla-at-uswest-dot-net>
Date: Sun, 13 Jun 1999 19:18:09 -0600
At 09:06 AM 6/14/99 +1200, "Malcolm Watts" <malcolm.watts-at-wnp.ac.nz> wrote:
> Great post:
>> Original Poster: Terry Fritz <twftesla-at-uswest-dot-net>
>> Hi All,
>> Here is a list of the losses in a Tesla coil I had laying around. I
>> forget the details but the numbers should be fairly typical. I think this
>> is an LTR design...
>> Primary Neon Windings = 29 watts
>> Secondary Neon Windings = 21 watts
>> Filter Resistors = 92 watts
>> Primary Circuit Loss = 490 watts
>> Secondary Circuit Loss = 17 watts
>> Power to Arc = 127 watts
>> Total = 776 watts
>> Note that almost half the coil's energy is being burned up in the gap.
>> Capacitor losses and primary coil losses are comparatively low so the gap
>> is eating power like mad...
>I realized this early on by considering the noise, light and heat in
>the gap. BTW, a gap that is loud compared to the secondary discharge
>means something can be done to considerably improve output at the
>same power level.
The terrible gap losses can be significantly reduced by good quenching
trapping the primary energy in the secondary system so that it cannot be
chewed up in the wasteful gap. Of course, good quenching is much more
easily said than done.
I would like to try a series gap like the ones I made from copper pipe
sections in series with a rotary next. Rotaries tend to be poor quenchers
despite their other favorable characteristics. Even timing critical LTR
systems can support additional series gaps since the rotary still controls
Backing off the coupling seems to help quenching too without a great
effect on energy throughput. With lower coupling, it just takes a bit
longer to transfer the energy to the secondary. However, if lower coupling
allowed better quenching, the small energy loss caused by lower coupling
would be far outweighed by the advantages of good quenching.