Understanding Magnet Polarity: Magnetic Confusion

[Woodski]

I made myself an electromagnet and did a small experiment involving it and a permanent magnet. When I switched on the electromagnet it attracted the permanent magnet. I made the assumption that they were opposite poles, hence making them attract. However, I changed the current direction of the electromagnet thinking that it would then repel the permanent magnet. However, it also attracted the permanent magent. This has left me highly confused about the polarity of magnets. Can someone please help?

 

[Mentz114]

You should give full details of your experimental setup. It sounds as if you made a mistake with your polarities but without seeing the alignments of magnet and coil one can't be sure what's happening.

 

[wiredGuy]

was the permanent magnet's facing side always the same?

 

[Woodski]

The electromagnet is made with am iron core with insulated copper wire wrapped around it. The power source is a transformer from my sons train set. When I move the permanent magnet to the top of the electromagnet it is attracted. If I turn the permanent around so the opposite pole is pointing towards the same end of the electromagnet then there is a bit more buzzing by the electromagnet but again the permanent magnet is attracted to it.

 

[ranger]

The electromagnet is made with am iron core with insulated copper wire wrapped around it. The power source is a transformer from my sons train set. When I move the permanent magnet to the top of the electromagnet it is attracted. If I turn the permanent around so the opposite pole is pointing towards the same end of the electromagnet then there is a bit more buzzing by the electromagnet but again the permanent magnet is attracted to it.

Umm...Seems like you need to rectify the AC current from the transformer to get a DC current to be able to change the current direction through the electromagnet.

 

[Mentz114]

Yes, make sure you've got DC. Another possibility is that the permanent magnet is magnitudes stronger than the electro-magnet.

 

[Woodski]

I believe the transformer is AC-DC. I guess it is just because the magnitudes of the permanent magnet are stronger. However, I would still have thought that they would have repelled because if you have a strong and weak permanent magnet, they will repel. So I am still confused.

 

[Mentz114]

Try removing the metal core of the electromagnet. It could have become permanently magnetised.