Talk:Neon-sign transformer

questions

Dear sir,

Is it possible to generate Infra Red light waves instead of other colours in Neon signs.?

maheshkrishnan@avalontec.com

My humble Answer: This sound like a Laser--a close cousin. Try googling/wiking IR lasers.

Also. most Neon signs are filled with neon; if you want any color other than "clear red" you need use tubing with a colored fluorescent coating to produce the color. The small amount of UV invariably produced by the excited Neon (Plasma) lights the coating. Other gases, like Krypton, Xenon, etc, produce different colors but are very rarely used. They are expensive. There Is a mixture in those Plasma Globes you see. [Special:Contributions/70.176.118.196|70.176.118.196]] (talk) 14:25, 9 April 2011 (UTC)

Types?

Please mention no Neon transformers were ever made over 60 mA output. Any devices over 60 mA are for bombarding (bench burning-in of Neon tubes) and are not current-limited. This is done externally with a Variac in series. (Claude Neon.)

Also, an AC transformer is 98% efficient--the switch mode "electronic Ballast"--type do Not exceed this efficiency. They are only lighter, quieter, and won't drip tar on the rug if they get hot. I repaired switching, and occasionally linear, power supplies 8 years. Switch-mode Electronic Ballasts are simply 85% efficient compared to the 35% or so of a linear power supply.

Switch-mode transformers are No Good for Tesla coils--the back RF will fry them, instantly. Plus they are not designed to work into a capacitive load. Perhaps an RF filter can be added, but their switching frequency of 15-25 kHz sometimes approaches the operating frequency of the Tesla coil, and precludes this. They are also designed to run into short-circuit conditions just like a transformer-type--they would Have to. Otherwise you could not directly substitute one type for the other as I do. They can also run open-circuit for at least a short while or they couldn't light a Neon sign--they would "shut down" and not provide the high voltage starting pulse. This takes about 1/2 second or so.

An RF filter must always be added between the output of a transformer-type NST and a Tesla coil, or the back EMF can cause internal carbon shorts in the asphalt potting. These can be fixed by removing the tar, but it is very delicate, messy work.

Transformer-type NST's have a center tap (grounded) when they produce about 10 kV or more. This makes for two hi voltage output windings, insulated for 1/2 the output. Saves insulation and costs. It is also safer to operate in this manner.

The magnetic shunt current-limit in a transformer-type is a split in the normal "tongue" of the center lamination that is designed to reduce flux as load current increases.This is the opposite of a normal transformer, which will provide much more current, momentarily, than designed for if shorted, unless secondary resistance prevents this and/or it burns out a winding.

The current limit is designed to allow a high voltage starting "pulse" to the tube, then to limit current, and, hence, power to the tube. The short-circuit current is equal to the rated current, an AC ammeter can simply be placed across the hi voltage outputs to test it. The average short-circuit/full-load output voltage is 800 volts.

Also, the asphalt in old-fashioned transformers is for Noise--not weatherproofing or insulation. They are well-sealed in a steel box for outside use. The newer ones for indoor use are potted in epoxy. They will run fine without tar--in fact, if asphalt removed (Very Carefully!), and they are immersed in oil, the shunt can then be bypassed for safe, short bursts of even greater current. There is much less chance of an internal short, too.

Also, many newer transformer-types have ground-fault interrupters ("GFI's") built-in, which will trip/fry if it is used in a Tesla coil. These should be obviously not be used in Tesla coils, or the GFI removed/bypassed.70.176.118.196 (talk) 14:17, 9 April 2011 (UTC)

WIth respect you are wrong about current. It is easy to find transformers that go to 100 mA e.g. this. You sound knowledgeable, but you really should read WP:OR and realise that Wikipedia is based on verifiability. --Biker Biker (talk) 15:16, 19 May 2011 (UTC)

I have checked your reference; these are very new switch-mode types for 230 VAC input, only. Not for General use, these are the Odd Man--the fact most (90%) are not made over 60 mA is still a valid general rule. I have a friend with a friend who runs a Neon shop; in 3 years he's Never seen an NST come in with even 60 mA output. He has old catalogs from the 'fifties with them in it. But they are considered old and rare in the Americas, where much Neon is. So, they are Not :"easy to find"; they are foreign and take extra shipping. Not generally Available, at least in the Americas, or, Japan, where Neon is much more prevalent. They are rated for Cold Cathode, which is a different form of lighting. Many everywhere are going to LED's, anyway, to save expense and energy; so your source may dry up very soon.

Besides; article says/said: "Most". Check its semantics and context. The use of 60 mA is still correct. 60 mA units were made, but even they are are hard to find (I checked Neon shops all over Napa and Tucson; NO (zero) 60 mA units were found/available.) Your 100mA/230VAC units are a rare exception.

Generally, if more than 30 mA is needed, more transformers are coupled together. Most neon tube runs are designed not to exceed the 15 kV/30 mA limit so as to not need more than one transformer or an odd, 230-Volt unit. By "run" I mean, not more than one letter, or,"segment", is designed to exceed this general rule.

I have Worked with Neon; at least in the 'states where 110 VAC input is the rule unless very hi-power is needed. The 15kV/30mA general rule is in effect. Even 15kv/60mA units are hard to find, as I said, but have been used.

Yes, I am Knowledgeable; 4 years in college plus 8 years repairing switch mode/linear power supplies is "real" knowledge. And, the input of engineers at work.

Why are you Always Criticising me? What have I done, Personally , to you? I don't just say things to hear myself talk, I either have a reference (Claude Neon) or first hand experience.68.231.184.217 (talk) 04:39, 24 May 2011 (UTC)

First hand experience is original research - it's a clear and simple policy. --Biker Biker (talk) 07:30, 24 May 2011 (UTC)

Giving someone benefit-of-the doubt and not just sitting on your duff and Googling something is just being Civil. I will get a few Neon shops here to verify and use them for reference. And, Jefferson and Franceformer catalogs. Remember, Most Neon is in the Americas or Japan; 120 or 100 VAC. No one will buy a transfomer adapter to 240 or 347 VAC to use a 120mA transformer they had to order special and pay extra shipping. They'll just blow a smaller section or use two transformers. This makes your 120 mA not "readily available". Time is Money.68.231.184.217 (talk) 23:40, 21 June 2011 (UTC)

Like I say, go read WP:OR. WIkipedia is based on verifiability, which trumps truth every time. --Biker Biker (talk) 23:42, 21 June 2011 (UTC)