11
   

Why oh why won't my "simple" electromagnet work?

 
 
DrewDad
 
  1  
Reply Wed 24 Mar, 2010 10:08 am
@boomerang,
Can you show us a pic of your setup?
0 Replies
 
DrewDad
 
  1  
Reply Wed 24 Mar, 2010 10:10 am
@Rockhead,
Er...

The wires are basically a short circuit. Too high of a voltage will get you some interesting pyrotechnic effects.
0 Replies
 
boomerang
 
  1  
Reply Wed 24 Mar, 2010 10:18 am
I've got to head out to the dentist in a minute so I'll try to describe it...

We used a large allen wrench (I don't know the exact size but it's about 4" long and maybe 1/4" around) as the base after testing it to make sure it was magnetic.

We wrapped copper wire all along the lenght of the allen wrench.

We burned the coating off of the ends of the wire.

We "crimped" the ends of the wire to make a larger contact point.

Using electrical tape, we taped a battery (first a "D", then a 9v) to the allen wrench.

We taped the wire to the the - end of the battery.

We touched the + end with the other end of the wire.

Nothing happened. Well.... the battery got hot after a bit but it wouldn't even pick up the tiny nails that the small magnet we made would pick up.
DrewDad
 
  2  
Reply Wed 24 Mar, 2010 10:27 am
@boomerang,
With coated wires, it's really easy to scrape off some of the coating and get a short between your iron bar (allen wrench, in this case) and the wire. If that happens, I think your magnet won't work.

Battery getting hot is actually a good sign; it means you have a complete electric circuit.
boomerang
 
  1  
Reply Wed 24 Mar, 2010 10:35 am
@DrewDad,
So maybe I should try insulated wire? Would that cure that problem?
Rockhead
 
  1  
Reply Wed 24 Mar, 2010 10:38 am
@boomerang,
I use insulated wire...

0 Replies
 
Cycloptichorn
 
  1  
Reply Wed 24 Mar, 2010 10:39 am
@boomerang,
How many wrappings of wire did you do? One is probably not sufficient - I've made pretty strong electromagnets before and done dozens of layers of wrapping on them.

Anyway, this ought to work -

http://ktcatspost.blogspot.com/2007/01/homemade-electromagnet-project.html

Looks simple enough.

Cycloptichorn
0 Replies
 
dadpad
 
  2  
Reply Wed 24 Mar, 2010 10:50 am
I may have misled you. the coating on the wire only needs to be removed where it will contact the battery terminals.
I'm a bit concerned about the 9V battery. The coil may become quite hot and cause a fire or burn someone.
Quote:
Caution! Too much current can be dangerous! As electricity passes through a wire, some energy is lost as heat. The more current that flows through a wire, the more heat is generated. If you double the current passing through a wire, the heat generated will increase 4 times! If you triple the current passing through a wire, the heat generated will increase 9 times! Things can quickly become too hot to handle.


A D cell battery provides enough current to lift several paper clips or a small mass of iron filings

You may need to sand the wire contacting area before each use. Use a fine grade sandpaper.

When you wrap the wire around the nail, make certain that you wrap the wire all in one direction. Wrap neatly from one end to the other. More turns will increase the magnetic effect.

notes
Soft iron is a good temporary magnet. A steel nail will retain a lot of its magnetism once the current in the coil is switched off.
The battery will drain fairly quickly (in a matter of several minutes)
Usually the big problem is getting and maintaining a good contact at the battery terminals
0 Replies
 
boomerang
 
  1  
Reply Wed 24 Mar, 2010 02:54 pm
Armed with all this knowledge (thanks again, everyone) we hit the hardware store. The guy working today had some experience with this experiment!

We found a large bolt (smaller than the allen wrench), insulated wire, and a 6v battery.

Mo's out goofing with friends this afternoon so we haven't had a chance to build it yet.

Fingers crossed....
0 Replies
 
boomerang
 
  1  
Reply Wed 24 Mar, 2010 04:51 pm
It works! It works!

You guys are the best!
0 Replies
 
boomerang
 
  3  
Reply Thu 8 Apr, 2010 04:46 pm
Thank you all so much for your help in making Mo's electromagnet work!

He gave his speech today and did so well that I thought he was going to bust wide open.

I was out in the front yard when he was walking home from school and the minute he saw me he started yelling and running and couldn't wait to get out his score sheet and show me.

HIs confidence has shot up a mile.

Thank you, thank you, thank you.
djjd62
 
  1  
Reply Thu 8 Apr, 2010 04:47 pm
@boomerang,
nice, way to go mo
0 Replies
 
sozobe
 
  1  
Reply Thu 8 Apr, 2010 05:10 pm
@boomerang,
Great!
0 Replies
 
mismi
 
  1  
Reply Thu 8 Apr, 2010 05:12 pm
@boomerang,
That is awesome Boomer! So happy for you and Mo.
0 Replies
 
Cycloptichorn
 
  1  
Reply Thu 8 Apr, 2010 05:16 pm
@boomerang,
Yeah!

Cycloptichorn
0 Replies
 
 

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