How many volts/amps for an electric arc between points?

In summary: Electron and ion drift can always cause voltage fluctuations and require attention, but it is usually not a big deal.
  • #1
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Can someone help me find these calculations or give me a point in the right directions?

If I have a hollow insulating cylinder (has a diameter of 5 cm and a length of 14 cm) with two (conductive) sharp metal point contacts at each end (measuring 2cm each leaving 10 cm exactly between the points). Inside the cylinder is normal atmosspheric pressure of standard air.

How do I calculate how many volts and amps I require to have a continuous electric arc between the contacts?

Thanks for your help and all answers are welcome.

:smile:
 
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  • #2
Thats a rather complicated question. To get any current flow at all you must first ionize, or breakdown the air. The breakdown voltage for air is roughly 3 million volts per meter - that varies with pressure and moisture content - so you need about 300,000 volts to start the arc. After that things get more complicated.
 
  • #3
First of all thank you mheslep for the speedy reply, I appreciate it.

I could use an array of extremely high voltage generators to produce 300,000 to 330,000 volts and a continuous 10cm electric arc (assuming a standard pressure and temperature air mix), but this would still be a process of trial and error.

One more question is:

Assuming the cylinder is closed to outside influence and the walls are a suitable insulator to temperature, would the voltage required to generate the discharge should drop when the temperature increases on a steady curve, just like the rising temp of a high voltage traveling arc (Jacob’s ladder)?

I still have not found how many amps are required but I will keep searching. :)
 
  • #4
mheslep said:
Thats a rather complicated question. To get any current flow at all you must first ionize, or breakdown the air. The breakdown voltage for air is roughly 3 million volts per meter - that varies with pressure and moisture content - so you need about 300,000 volts to start the arc. After that things get more complicated.

I get half that; 150KV. How did you arrive at 300?
 
  • #5
3 × 10^6 V/m

I have found several sources like hypertextboox qouteing the average votage for dielectric breakdown of air around 3 × 10^6 V/m I took this as a base line and divided 3,000,000 by 100 then mutliplied it by 10 to arive at 300,000 volts for every 10cm.

Exclueding the build up of ozone and nitrous oxide on the sharp metal contacts causing corrision of course.

Where did you get 150,000 volts for 10cm?

as always thanks for the reply.
 
  • #6
Doh! My mistake. 150KV per conductor. 300KV total, of course. But can one really ignore electron and ion drift?
 

1. How is the voltage and current of an electric arc between points determined?

The voltage and current of an electric arc between points is determined by the distance between the points, the type of gas present in the arc, and the temperature of the arc. The longer the distance between the points, the higher the voltage and current required to maintain the arc. Different gases have different breakdown voltages, which affects the voltage and current needed. And as the temperature of the arc increases, the voltage and current needed also increases.

2. What is the optimal voltage and current for an electric arc between points?

The optimal voltage and current for an electric arc between points can vary depending on the specific application. However, it is generally recommended to use the lowest voltage and current possible to maintain the arc, as this reduces energy consumption and potential damage to the equipment.

3. How does the composition of the electrodes affect the voltage and current needed for an electric arc between points?

The composition of the electrodes can affect the voltage and current needed for an electric arc between points. Different materials have different electrical resistances, which can impact the breakdown voltage and current needed for an arc to form. It is important to choose electrodes with appropriate resistances for the desired voltage and current.

4. Can the voltage and current of an electric arc between points be controlled?

Yes, the voltage and current of an electric arc between points can be controlled by adjusting the distance between the points, the type of gas present, the temperature of the arc, and the composition of the electrodes. These factors can be manipulated to achieve the desired voltage and current for a specific application.

5. What safety precautions should be taken when working with electric arcs between points?

Working with electric arcs can be dangerous and should be approached with caution. Proper protective gear, such as gloves and goggles, should be worn. The equipment should also be inspected regularly and maintained in good condition. Additionally, proper training and knowledge of how to handle electric arcs safely is crucial.

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