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NEON- Re: dimming stage neon
Taine,
>>>The primary benifit the manufacturer claims for dimmers which dim via reverse
phase cut using IGBTs is that it greatly reduces noise and eliminates the need
for a choke. We were discussing if this type of dimmer would be more suitable
for dimming a neon transformer.<<<
Hate to put a damper on this, but I see big problems using 'reverse phase cut'
for dimming neon. The problem is this method turns off the switching device
(IGBT) while the current is still flowing into the load. This is no problem for
a resistive load, like a lightbulb, but an inductive load, like a neon
transformer, is going to resist any radical current change by generating a
vicious voltage spike (which will probably damage the IGBT switching device.)
In the SCR / triac method, the switch turns off when the current going through
it goes to zero. While with an inductive load this is slightly past the zero
voltage point, it is where the energy stored in the transformer is zero - thus
no back-EMF problem. For what it's worth.
Regards,
Telford Dorr