neef vibrator/ spark gap/ assembly questions

[brycecelano]

I have a couple questions about the neef vibrator and spark gap circuit. How did other people connect the components? The project doesn't mention wiring them together. Should I use a third wire type and/or solder them directly together? Does anyone have a picture of their finished project they wouldn't mind sharing? What method did you use to wrap the outer coil? I had trouble finding an iron core in 5/8th diameter is the inner coil circumference going to change the size of the magnetic field?

[staryl13]

Hi!
Other people have asked similar questions on this forum before. You might want to look at some of the other posts, such as this one:
http://www.sciencebuddies.org/mentoring ... php?t=3105
Good luck with your project!

[brycecelano]

I read that thread and several others regarding the assembly but there are still several items that are unclear. If the primary(inner) coil is wrapped around the bolt wouldn't it be shorted out and not have the effect of a coil? Why does the project require bare copper wire for the inner coil it seems like insulated wire would make more sense.

[Louise]

I read that thread and several others regarding the assembly but there are still several items that are unclear. If the primary(inner) coil is wrapped around the bolt wouldn't it be shorted out and not have the effect of a coil? Why does the project require bare copper wire for the inner coil it seems like insulated wire would make more sense.

It should not require bare wire. This is a typo that was supposed to be corrected. You are right about that. One of our other experts had these comments on the project:

Using the bare (uninsulated) 12 AWG copper wire in the material list for the primary is wrong. When it is wound on a metal bolt, it WILL short circuit the coil making for a poor electro magnet and a poor electro magnetic field for a transformer. Type TWHN solid 12 AWG copper wire or similar should be called for.

The relay is shown incorrectly. The normally closed contacts should be oriented away from the bolt head so that when current flows, the primary and bolt act like an electro magnet and open the contact. The normally closed contacts should be wired as shown, it is just the mechanical orientation that is wrong.

The description of the building of the apparatus should indicate that the Neef vibrator should be constructed and tested and be in good working order BEFORE winding the secondary! This should be done to allow working with the circuit without the high voltage danger!

Staryl13 is correct that there is a wealth of information about this project on the forums. I recommend doing a search on this project, since it is fairly complicated. I also found the original instructions (linked to off the science buddies page) is a little bit more detailed:
http://www.bizarrelabs.com/ind1.htm

There are also figures for the different parts of the project. They are linked to at the bottom of the bizarrelabs page.


Good luck,
Louise

[brycecelano]

I've read the entire thread that's mentioned as well as the original application (it uses a significantly different coil and vibraor creation method). It was obvious that the normally closed contacts needed to be held "away" from the iron core by the spring so I didn't notice the wording was wrong. I had already taken the insulation off my wire so I used a large plastic straw to insulate my iron core from my primary coil. It's a little complicated making the neef vibrator out of the part from radio shack because the head of the bolt actually needs to be on the inside of the frame that holds the spring and contacts. I was able to drill out the frame and pass the iron core through the hole but if your core was too fat you might need to build a new larger frame out of sheet metal.

Just a note for future readers, the amount of enameled wire in the parts list is far too low in order to get the required number of turns and joining the enameled wire to itself is a little bit cimplicated when you splice in the new spool.

I still would love to see a picture of a completed project and here how someone else mounted the components.

[Louise]

I've read the entire thread that's mentioned as well as the original application (it uses a significantly different coil and vibraor creation method). It was obvious that the normally closed contacts needed to be held "away" from the iron core by the spring so I didn't notice the wording was wrong. I had already taken the insulation off my wire so I used a large plastic straw to insulate my iron core from my primary coil. It's a little complicated making the neef vibrator out of the part from radio shack because the head of the bolt actually needs to be on the inside of the frame that holds the spring and contacts. I was able to drill out the frame and pass the iron core through the hole but if your core was too fat you might need to build a new larger frame out of sheet metal.

Just a note for future readers, the amount of enameled wire in the parts list is far too low in order to get the required number of turns and joining the enameled wire to itself is a little bit cimplicated when you splice in the new spool.

I still would love to see a picture of a completed project and here how someone else mounted the components.

Please don't post your email here. It is a violation of the terms of the forum (and will probably be removed by the moderators).

I'm glad you realized the relay wording was wrong. No procedure is 100% correct; so thinking about _why_ you do each step is important. (Just like with the insulated wire- I am pretty sure the 'list of materials' contains the typo calling for uninsulated wire, but I think the text description calls for the insulated wire (like you might expect)). Anyway, glad you got the idea to use a straw to insulate, and I appreciate that you took the time to post back with suggestions for future readers.

I hope you have a fun science fair!

Louise

[brycecelano]

does anyone have a picture!!!!!!!! of this porjsect finished i would really appericate it.