Science Buddies project "create your own spark"

[VM2061]

Hello.
I am sorry to have to ask questions but this is an important project for me. My Dad is helping me build the induction coil for the project above.
We have the 5/8in carriage bolt wrapped with the 30in of 12 gauge wire. We left 2 1 in pigtails for connection. Now we left the insulation on because otherwise the wire would be shorted out in contact with the bolt. It came out to 12 turns on the primary coil.
The material list has 250in of 25 gauge or higher enamel magnet wire.
The PVC we are using that fits the primary coil perfectly has a circumference of 3.5in (approximatly). Using the formula Vs/Vp=Ns/Np and 12 volts on the primary we get 10000 turns for 10000 volts on the secondary. 10000 turns x 3.5in = 35000 in or almost 3000 Ft!! of wire. Is this right? Why does th materials list say 250in? Also what is the easiest and most accurate way of winding the secondary coil? Thank you.

[ghariman]

Hi there,

First of all there is no need to be sorry for asking a question. Why should you be sorry ?

Okay next the formula says that in order to ionize air you need to get 3000 (three thousand) Volts per mm distance between the gap. So say you make the gap on your secondary coild to be 1 mm then you would only need to generate 3000V on the secondary.

If you use 12V on your primary then this will produce a turns ratio of 1:250. That is if you use 1 turn on your primary then you would need 250 turns on your secondary.
If you use 3 turns on your primary then you would need 750 turns on your secondary.
And so if you use 4 turns you would need 1000 turns on your secondary.

Now on to your question regarding the length of secondary needed. It may be perhaps that in the instruction that they do not use a 3.5inch circumference PVC pipe. If you were to use a 1inch circumference PVC pipe instead and you use 1 turn on your primary and need 250 turns on your secondary then you would need only 250 inch length for the secondary.
So if you use 3.5 inch circumference for your PVC then of course you will need more length of secondary wire.

In terms of winding.....not sure. If you are able to attach your PVC pipe onto something that can rotate very fast (eg. bicycle tires, a dremel tool, a drill tool) you will have an easier time winding your wires. Ask your parent if they can help you do this.

As a last note: Please keep in mind the cautionary warning that they have put in the test description page => BE CAREFUL OF VERY HIGH VOLTAGES on the secondary coil. IT CAN KILL !!! READ THE INSTRUCTIONS OVER MANY TIMES AND QUADRUPLE CHECK YOUR SETUP EVERYTIME !

In addition I need to say this as a disclaimer because of the nature of the experiment you are doing: I do not claim to be an expert on this matter and I am not a health expert either. So use this advice with your own risk.

Good luck !

[VM2061]

Hello.
Thank you for the help. I understand now. Because our primary has 12 turns on it and we are using 12V then the amount of turns = the secondary voltage. So if we want 3000V for 1mm we need 3000 turns. For a cm we need 30000 turns which is two much wire. The materials list says a 5/8in carriage bolt. The bolt alone has a circumference of about 1.96in. My father thinks they may mean a HEAD SIZE of 5/8 in making the bolt diameter much less.
We used the 30 in of wire resulting in a 12 turn primary. I think we are going to try for a 3 to 4mm spark which means 9 to 10000 turns. We also just realized if we double the voltage on the primary we only need half the turns to get the same voltage on the secondary.
My father has been in electronics for a long time and knows about the hazards. He says we will be very safe with this. He also wants to know if you want a credit written on the project board. We can also send you pictures of the finished project. Please let us know.

[ghariman]

Hi,

If you are going to put up any credit, please credit this website "SCIENCEBUDDIES.ORG". There will be no value if you put my name on your board. But putting the SCIENCEBUDDIES name on the board will inform other students/teachers the importance of this website and hopefully let other students/teachers use it more in the future !

Yeah I would like to see the picture of the finished thing.
Email it to [email protected] and the Science Buddies staff can forward it to me.

Thanks !

Hello.
Thank you for the help. I understand now. Because our primary has 12 turns on it and we are using 12V then the amount of turns = the secondary voltage. So if we want 3000V for 1mm we need 3000 turns. For a cm we need 30000 turns which is two much wire. The materials list says a 5/8in carriage bolt. The bolt alone has a circumference of about 1.96in. My father thinks they may mean a HEAD SIZE of 5/8 in making the bolt diameter much less.
We used the 30 in of wire resulting in a 12 turn primary. I think we are going to try for a 3 to 4mm spark which means 9 to 10000 turns. We also just realized if we double the voltage on the primary we only need half the turns to get the same voltage on the secondary.
My father has been in electronics for a long time and knows about the hazards. He says we will be very safe with this. He also wants to know if you want a credit written on the project board. We can also send you pictures of the finished project. Please let us know.