High Voltage Neon Power Supply Gaseous Tube Transformers
As I mentioned on the what makes neon glow page, we need something to convert ordinary household 120V current into the high voltage needed to excite the electrons inside the neon or argon tube. These needed higher voltages are created by transformers. That is how a clear glass tube on a neon sign will light up in that famous reddish-orange glow, with the high voltage produced by the transformer when powered up. A transformer is a common electrical item. Transformers come in so many different ratings and sizes, there are whole websites devoted to them. Sometimes a transformer is needed to lower voltage such as with a computer printer or desk calculator. Neon signs use "gaseous tube " transformers. Transformer output voltage is intended for lighting neon tubes. Gaseous tube transformers are special. They have a high voltage output rating and a low ampere output rating. That is what makes a gaseous tube transformer different from the rest.
In a neon tube sign application we do not want a high amp flow. Ever have a electrical plug short out when you put it into a wall outlet? The spark that made was the voltage. The burnt pit or chunk of missing metal on the blackened plug was the amps. Old neon beer signs or commercial neon signage use heavy wire-wound transformers to bring the voltage up to the required output while leaving the ampere rating low. Needless to say, a neon sign transformer can "light" you up almost just as well as a neon tube! Precautions handling neon signs is a good place for some do's and don'ts of neon signs.
Most newer neon signs use lightweight solid-state transformers. They still do the same job, just in a different manner. A small neon clock will have a solid-state transformer about the size of your thumb. That is because approximately 1.5K of voltage will light the tube satisfactorily. It's a small diameter tube and it travels only so far. A typical beer neon sign may have 2 or 3 or more tubes comprising the entire sign. Therefore more voltage is needed to light all the tubes. If you look at a typical neon tube beer sign transformer, you will see something like this on the label:
Pri 120 V 225 mA Sec 9000 V 30 mA
That would translate as: Primary voltage (source power) is 120 volts. The mA stands for milli-Amps. In the example the input flow required is 225 milli-Amps. Secondary voltage is 9,000 volts at 30 milli-Amps. Now 9K of voltage is a lot of volts, but 30 milli-Amps is a really low number. This is because as I stated before, neon likes a high push but rather cares less about the flow (amps) being high.
Another thing you commonly notice on a gas tube transformer is most say "secondary mid-point grounded". So what does that mean neonaddict? Well, it means the voltage halves of the transformer shares a common midpoint ground. This grounding is internally done directly in the middle between the transformer coil halves. Since it shares the ground, how can it function properly if the ground is incomplete? Technically, it doesn't. The outlet it is connected to needs to be properly grounded as well. Won't just a hot and a neutral light it? Answer - yes. Problem is there is no ground path when a fault occurs. I've been zapped by a neon transformer. It sucks. It is very hard to control what you break when you are shocking yourself. I've also been zapped by a car ignition coil. That's even worse! The amps are higher!
I purchased some good used neon channel letter transformers 11/10/08. These transformers are designed to fit inside channel letters, under the tubing. They were pulled from a working environment as power for channel letters and some skeleton outline neon tubing. Like usual, I bought more than I needed. So, I am making available for sale these tested good used neon transformers. These transformers are designed to be hard-wired in and inside an enclosure. For home or shop use you will at minimum need a three conductor cord with a good ground plug. Yes, you could use that lopped-off old 3-prong appliance cord you cut before you tossed the appliance out. See the tables below for specifications on these units.
| 4K Ventex |
 |
|---|---|
| Input: | 120V 0.3A 50/60 Hz |
| Output Voltage: | Self-adjusting 0.5 to 4KV @ 30mA RMS |
| Power factor: | High .95 |
| Model: | VT4030CL-120 |
| Type: | Outdoor Type 3 |
| UL: | Listed, UL2161 compliant |
| Length: | 5 inches |
| Width: | 1¾ inches |
| Height: | 1¼ inches |
| Bolt pattern: | 3 at 4½ inches center |
| Weight: | 1 pound un-boxed. |
| Note(s): | Used. Picture(s) are example(s), not actual item. |
| Price: | Used. $15.00 plus shipping. |
| 6K Ventex |
 |
|---|---|
| Input: | 120V 0.3A 50/60 Hz |
| Output Voltage: | Self-adjusting 1 to 6KV @ 30mA RMS |
| Power factor: | High .95 |
| Model: | VT6030CL-120 |
| Type: | Outdoor Type 3 |
| UL: | Listed, UL2161 compliant |
| Length: | 7 inches |
| Width: | 1-7/8 inches |
| Height: | 1-5/8 inches |
| Bolt pattern: | 6 at 6½ inches center |
| Weight: | 1½ pounds un-boxed. |
| Note(s): | Used. Picture(s) are example(s), not actual item. |
| Price: | Used. $18.00 plus shipping. |
I will mention this again in case you missed it. You need a three (3) conductor cord. Ground is extremely important in neon lighting. It needs to exist for safe and proper function. Transformers are grounded - period.