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Allen Brtadley pilot light question

Some allen bradley pilot lights or lighted pushbuttons accept a 110 vac input to drive a 6 volt 1966 incandescent pilot light. One example is their 800T-PB16.

The stepdown circuit appears to be something of a mystery and not a transformer as infinite resistance is measured on the 110 vac lamp terminals. And using a capacitor alone for a bulb drop is really dumb because of possible surges destroying the bulb.

At any rate, if a modern LED replacement for the 1966 is used, the load current will be much lower.

Will their circuit handle this, or will the LED blow out from overvoltage?

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Many thanks, 

Don Lancaster                          voice phone: (928)428-4073 
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552 
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com 

Please visit my GURU's LAIR web site at http://www.tinaja.com
Reply to
Don Lancaster
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Does the unit still work? I know some definitely had a TINY transformer in the back of the fixture, and the windings must have been made with insanely fine wire. So, I'd check to make sure the unit isn't actually defective.

I can't imagine they used any serious electronics in 1966 for this purpose. (Or, is 1966 the bulb number? But, I can't find one of those.) Is there any possibility this unit has the wrong lamp in it? If it was for a neon lamp, it would have a series resistor, and would appear open circuit with the neon bulb in place.

Jon

Reply to
Jon Elson

Oops. It was a GE 1866 bulb.

Lights up just fine, so the circuit still seems to work.

Not very bright, but incandescent with a strong green filter is not very efficient.

--
Many thanks, 

Don Lancaster                          voice phone: (928)428-4073 
Synergetics   3860 West First Street   Box 809 Thatcher, AZ 85552 
rss: http://www.tinaja.com/whtnu.xml   email: don@tinaja.com 

Please visit my GURU's LAIR web site at http://www.tinaja.com
Reply to
Don Lancaster

They seem to have two kinds of transformers for this. One is exactly what you'd expect: two 120 V gozintas, two 6.3 V comesoutas - 800T-N326.

The other kind has *three* 120 V gozintas and two comesoutas, and either has a relay (800T-N296) or some diodes (800T-N920N) inside. This seems to have something to do with providing a "lamp test" input that's independent of the "regular" input.

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If you have the three-gozinta kind, you have to pick the right two gozintas for the ohmmeter. I think.

Matt Roberds

Reply to
mroberds

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