question: how can input ac phase be delayed


This is a question from Lou Balint regarding his TC magnifier project.

Overview:    Lou built a magnifier that uses two power supplies, two 
sync rotary gaps, two caps and primaries, and two secondaries, all
driving one extra coil.  When both systems are fired up, the energy
adds together and increases the spark length compared with the
spark length when just one in running.  Lou demonstrated this TC
at Ed Wingate's recent Super-Teslathon, unfortunately some of the
spectators left before the final magnificent results were obtained.

Purpose:   Lou reasons that in a giant system, such a method of 
feeding the power from separate units might reduce the stress on 
individual components, permiting a larger system to be built.

Some details:    Since both gaps are 120 bps sync, they "want" to fire at
the same time (to be at the peak).  However if they do fire at the same
time, the RF tends to cancel due to imprecision in the rotary gaps, as
would of course be expected.  As a result, it is necessary to set the
gap phases so that one gap fires just after the other system rings down.
This way they still fire near the peak, but the RF from one firing doesn't
interfere with the RF from the other firing.  Since two firings are occuring
per half cycle, this is really a 240 bps system, although the individual
rotaries fire at 120 bps.  However unlike a standard 240 bps system, 
here the two firings occur very close together in time, then almost a 
full 120th of a second passes before the next "double firing".  

The question:   To overcome the compromise of not firing at the
absolute peaks, Lou would like to delay
the incoming AC to one of the system's transformers so that the 
systems could both be fired at their true peaks, while still preventing
the bangs from occuring at the same time.  Can anyone suggest a
method to delay the phase to one transformer?  I suppose some sort
of series capacitor array could be used, but I'm not sure how well it
would work, or exactly how it would be designed.  I seem to 
remember reading about a system that used various stages of
capacitive delay, but I forget the details.  A rotary converter
would be another option, but might be inefficient.  Lou does not have
access to 3 phase power.  Total input power range is 1kW to 2.5kW,
in his present small demo set-up.

Actually he could just adjust his ballast a little differently to one of
the transformers (with a possible slight power factor penalty), and get
some charging delay that way.  But still, he'd like to be able to get a
larger range of delay to the input to compare differing amounts of 

John Freau