Neon Transformers

[emahler]

looking to get some information on properly sizing neon transformers.

we have a situation where a marquee has neon lettering, with a total of 3 transformers.

2 are 7.5kv 30mA, and 1 is 9kv 30mA.

the letters that are being fed by the 9kv are the problem. then are not illuminating fully.

long and short, customer has tried to get neon sign companies out, no luck. we're the house electricians, so I got a plea for help...

the biggest question - what will happen to neon lettering if you send too much voltage in?

 

[cadpoint]

You might search here someone posted about a year + ago, some literature on the subject of neon signs, servicing, repairing, etc... as I recall...

 

[G._S._Ohm]

http://www.neon-lighting.com/techical/Tube-Troubleshooting.htm
The more voltage across the tube, the less current through the tube [negative resistance, just like in a welder's arc].

 

[LarryFine]

Maybe the wrong transformer is connected to the wrong letters.

 

[220/221]

The problem generally isn't the transformer. The extremely high voltage tends to short circuit. VERY common problem. Installing a larger transformer is a rookie mistake and will only temporarily fix the symptoms.

Add up the footage and do some math (google) to determine proper transformer size.

Start checking the wiring for shorts. The most common place for failure is the leads from the transformer.

Neon can be a PITA.

what will happen to neon lettering if you send too much voltage in?

It may temporarily make the letters brighter but the faulted wiring will just burn faster. A lot of times you can hear the fault buzzing.

 

[Cavie]

It could be a problem with the gas inside the letters. Are the individule letters or a complete run. A poor vaccume can cause poor lighting.

 

[G._S._Ohm]

It could be a problem with the gas inside the letters. Are the individule letters or a complete run. A poor vaccume can cause poor lighting.

The V-I curve of the tube may confirm this, and you can plot this curve by putting the 'frmr on a Variac. Somebody must have these kinds of spec's.