In one experiment, I compared the performance of a 2 gap 120 bps sync rotary
to a single 120 bps triggered static gap. In both cases I got a 42" max
spark length using my TT-42 TC. Using the rotary, the gap light and sound
emitted was quite low. Using the triggered gap, the gap light and sound
emitted was intense. The gap spacing when the rotary fired was small.
The gap spacing of the triggered gap was large at 5/8". Unfortunately I
don't
remember if I measured the firing voltage in both cases, but input power
draw was the same. The triggered gap
may have been capable of firing at a higher voltage for some reason. I have
speculated in the past that rotaries may not be capable of truly firing at
a peak voltage because of the way the voltage rises as the electrodes
approach. I'm not sure if that's a valid idea. If both systems fired at the
same voltage, then it's interesting that they both gave the same spark
length despite the very wide triggered gap spacing. One might say that
the 2 gaps of the rotary introduced extra losses. Yet in other experiments
I compared the performance of 2 gap and 4 gap rotaries, and didn't see
a difference in spark length output. Perhaps some slight quenching
differences occurred such that the negative and positive aspects
canceled. Various multi-pipe gaps were tried on this coil and the sparks
were considerably shorter and more feeble looking. I reported all these
results in the past. I'm re-posting them for the benefit of new list
members.
John