Re: neon flasher problem

Rasi,

you may have an interesting problem regarding the transformers

when you suddenly turn off an iron core transformer, it retain the flux
level it was at at turn off in the core. The next time you turn it on
,the flux level continues from where it left off....

If by chance, the xformer is turned off at the peak of the AC wave, it
will retain a large flux level. If by chance it is turned on at the
zero crossing , the flux level will try t oincrease from the high
starting point and can possible go into saturation. If this happens,
the inductance goes way down and thew current way up. This lasts for a
cycle or two and is very damaging to the contacts.

Solutions? Some kind of soft turn off and soft turn on.. maybe a low
wattage incandescent bulb wired ACROSS each relay contact ( the
incandescent light will be on when the neon is off.) This will allow
the core to turn off softly and become demagnizied and will allow some
low level of current to flow. Also maybe a slow start PTC device in
series with each transformer to limit the inrush turn on current.


good luck

Mark

.

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