Why isn't my electromagnet working?

[KaleLetendre]

In my adventures through my attempt at a home laboratory i decided i would try to play with electricity a bit more.

I took an iron cylinder 1 inch diameter 6 inch length and wrapped about 4 meters of 1mm copper wire around it with a small length hanging off each side.

To my understanding when i touch each side to a power source the result would be the magnetized iron, this was not the case. What did i do wrong?

 

[DrClaude]

Is the copper wire insulated?

 

[KaleLetendre]

No its not

 

[KaleLetendre]

I got the copper wire from an old T.V. Where it was used in an inductor

 

[DrClaude]

No its not

There you go, you just built a big, straight wire.

The make an electromagnet, the current has to flow in a spiral around the core. You need insulated wire for that.

I got the copper wire from an old T.V. Where it was used in an inductor

If it was used in an inductor, then it should be insulated. It is possible that the insulation is broken (or melted), making short circuits.

 

[KaleLetendre]

Ok i get it so i could say wrap the wire in electrical tape and then coil it and it should work

 

[jtbell]

If you still use non-insulated wire, make sure the individual turns don't touch each other.

 

[DrClaude]

If you still use non-insulated wire, make sure the individual turns don't touch each other.

You need also to put some tape around the iron core to isolate it.

 

[sophiecentaur]

If it was used in an inductor then it must be ok for the job. There must either be an open circuit (is there any way for you to know current is actually flowing?) or a flat battery or a short between the ends of the coil.
With the amount of current that cell could probably supply, you could expect to see small sparks when you brush one of the contacts with one end of the wire.

 

[sophiecentaur]

Thinking about this some more I guess that you just cut the wire and didn't strip the clear laquer insulation from the ends and there is no electrical contact. Try scraping gently with a knife or with emery paper. Alternatively, applying a hot soldering iron with solder may well dissolve the laquer and give it good 'tinned' ends for a good contact. I am sure that will sort out your prob.

 

[davenn]

Is the copper wire insulated?

No its not

I got the copper wire from an old T.V. Where it was used in an inductor

well actually if it came from a coil in an old TV ... it WILL be insulated, else it wouldn't have worked for that coil

What you haven't done is scrape the enamel insulation of the ends of the wire
so use a razor blade, craft knife etc and scrape the almost clear enamel insulation of around an inch off each end
THEN it will have proper connection to the batterycheers
Dave

PS ... I didn't read sophie's post fully ... in full agreement

 

[KaleLetendre]

It works! Thank you all

 

[davenn]

It works! Thank you all

well done

scraping the ends of the wire did the trick, I assume ?cheers
Dave

 

[sophiecentaur]

It really is unfair that they use so much 'gold' coloured laquer. Many other colours are available and everyone would spot a red or purple wire isn't plain copper.

 

[davenn]

It really is unfair that they use so much 'gold' coloured laquer. Many other colours are available and everyone would spot a red or purple wire isn't plain copper.

so true
... a nice trap for young players