Sizing a neon transformer involves determining the correct voltage and amperage output needed to power your neon tubing effectively, considering factors like length, gas type, and diameter.
Here's a breakdown of how to properly size a neon transformer:
1. Determine the Total Length of Neon Tubing
The first step is to calculate the total length of all neon tubing connected to the transformer. Measure the length of each tube segment and sum them together. This total length, usually measured in feet or meters, is crucial for determining the required voltage.
2. Consider the Gas Type
Different gases require different voltages to illuminate. The two primary gases used are neon (red/orange) and argon (blue/white, with phosphor coatings for other colors).
- Neon: Requires approximately 12-15 volts per inch of tubing.
- Argon: Requires approximately 10-12 volts per inch of tubing.
Use the higher end of these ranges when dealing with smaller diameter tubing or intricate designs.
3. Calculate the Required Voltage
Multiply the total length of the neon tubing (in inches) by the voltage requirement per inch based on the gas type.
Example:
- Total Neon Tubing Length: 10 feet = 120 inches
- Gas Type: Neon
- Voltage per Inch: 15 volts
- Required Voltage: 120 inches * 15 volts/inch = 1800 volts
4. Determine the Milliamperage (mA)
Neon transformers are rated in milliamperes (mA), which represent the current output. Common ratings are 30mA, 60mA, and 120mA.
- Brightness: Higher mA generally results in brighter illumination.
- Tube Diameter: Larger diameter tubing typically requires higher mA.
- Transformer Capacity: Avoid overloading the transformer. Running a transformer too close to its maximum capacity for extended periods can shorten its lifespan.
As a general guideline:
- Small diameter tubing (less than 10mm): 30mA or 60mA
- Medium diameter tubing (10-13mm): 60mA
- Large diameter tubing (13mm+): 120mA
Consult manufacturer specifications for specific tubing and gas combinations.
5. Select the Appropriate Transformer
Choose a transformer that meets or slightly exceeds the calculated voltage requirement and provides the desired milliamperage. It's generally better to have a transformer with slightly higher voltage capacity than needed, as it won't harm the neon, but a transformer with insufficient voltage will result in dim or non-existent illumination.
- Voltage Rating: The transformer's output voltage should be equal to or slightly higher than the calculated required voltage.
- Milliamperage Rating: Choose the appropriate mA based on the desired brightness and tube diameter.
Example Calculation
Let's say you have a neon sign with the following specifications:
- Neon Tubing Length: 8 feet (96 inches)
- Gas Type: Argon
- Desired Tube Diameter: 12mm
- Required Voltage: 96 inches * 12 volts/inch = 1152 volts
- Milliamperage: 60mA (for 12mm tubing)
Therefore, you would need a neon transformer with an output of approximately 1200 volts and 60mA.
Important Considerations
- Transformer Enclosure: Ensure the transformer enclosure is suitable for the environment (indoor/outdoor).
- Safety: Always follow local electrical codes and safety guidelines when installing and working with neon transformers. High voltage is involved.
- Manufacturer Specifications: Always refer to the neon tubing and transformer manufacturer's specifications for the most accurate sizing information.
- Starting Voltage: Some gases (like argon blends) require a higher starting voltage. Select a transformer with sufficient voltage to reliably ignite the gas.
By following these steps, you can accurately size a neon transformer for your sign, ensuring optimal performance and longevity.
