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Sync rotary setup method


Hi all, (particularly sync rotary owners.)

For about the last month I have been dinking around with various
sync and async rotaries,  paying particular attention to
charging efficiency.  Some will remember a post several months
ago asking about modifying a TC to produce no sparks so that
measurements and fine adjustments could be made to the charging
system without the noise and danger of a 3 foot arc buzzing
around the toroid !

It was generally agreed that removing the secondary is BAD. The
problem is finding somewhere for the tank capacitor's energy to
go.

What I have done over the last few weeks,  is replace my primary
winding with a chain of 3 halogen filament lamps.  The 1000W kind
used for outdoor security flood-lights. I was originally hesitant
to do this,  because I feared that the filaments may "fuse" under
the high peak discharge currents.  However this idea seems to
work well and provides many advantages to anyone wanting to study
the charging behaviour or make fine adjustments to rotaries:-


1. There are no toroid sparks,  hence less danger and less noise.
   (Also a far safer environment for using an oscilloscope.)

2. Peak currents are lower.  The current when the spark gap fires
   is limited due to the resistance of the halogen lamps.
   This reduces wear and also dramatically reduced spark gap
   noise to a quiet buzz. (Even the safety gap made a quiet pop.)

3. Less RF interference.  Since the capacitor now discharges into
   a resistive load,  the energy is dissipated in an exponential
   type decay rather than the usual damped ringing.  Therefore
   there is little RF generated and I found that television
   interference was almost eliminated completely.

4. Lamp brightness provides an indication of power throughput.
   Adjusting rotary phase for maximum brightness may be a good
   alternative for those without a scope and HV leads.

5. Charging behaviour is the same as with a normal TC.  The
   substitution of the halogen lamps for the primary has little
   effect on the low frequency charging behaviour of the system.


I just thought I would share this,  as it has enabled me to
carry out many hours of work on sync rotary charging without
keeping the neighbours awake and messing with there TV's.
I guess it would work just as well for static gap and async TCs.

If anyone plans to try this please rate the series chain of lamps
generously for the power you expect to process.  I used three
1000W 240v lamps in series,  and they lit dimly while running at
600 Watt.  Also bare in mind what would happen if a lamp went
open circuit !  (Dangerous charge left on capacitor ???)

	Now back to making some real sparks !

					- Richie

					- In sunny Newcastle.