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Re: electronic neon transformers
Tesla List wrote:
> If the output from an electronic neon was rectified and suitably protected
> from the rf, probably by large chokes on the dc side, could one use an
> electronic neon in a tc?
> I cannot see why not, unless 32kHz presents any problems for the rectifiers
> that I am unaware of ?
> The electronic units are quite cheap for their power output against
> conventional transformers and have adjustable voltage and current limiting
> making them more versatile than the conventional units - the unit I have seen
> could be programmed to go from 3-9kV and 30-60ma.
The problem is solid state trannys (SSTs) have both ground fault and
open circuit protection. Basically if the load doesn't look
something like a neon tube, the tranny trips. If you want to go
inside and defeat the protection, the Allanson is probably the
easiest POS (piece o' s..t). Just a crappy little 555 square wave
generator banging a couple of power mos-fets. The gf protection is
the center tap return brought through a toroid transformer with the
secondary feeding a simple 1 transistor level detector. The ENABA
10kv tranny has erratic to non-existant GF protection. You could
take a chance but it is potted so if you get one that works, you're
Next, SSTs are rather intolerant of reactive loads. The mfrs warn
in large text to minimize the capacitive loading. Capacitive, in
this case is the few pF represented by the GTO wire in conduit and
the tubing above the sign ground plane. Whereas a magnetic tranny
will simply reflect reactive current out to the power line, SSTs
tend to dissipate the reactive power in the transformer and power
transistors. That is, if the reactive power doesn't cause the
transistors to fire when they shouldn't and let all the blue smoke
The last consideration is that SSTs don't output their nameplate
voltage. They output voltage to light an equivalent amount of
tubing. Since high freq drives neon better than 60 hz, the voltage
is lower. A typical 9kv tranny will produce 5-6kv.
Seems to me it would be a bunch easier to breadboard a switching HV
power supply using a 555, a SMPS power mosfet or two and one of the
low impedance auto ignition coils such as the HEI coil. More power
capability and none of the stuff needed to make 'em live on neon to
have to defeat.
John De Armond
Neon John's Custom Neon
"Bendin' Glass 'n Passin' Gas"