Thursday, May 1, 2014

Electromagnets and Motors

It's pretty easy to make a simple motor. We got excellent instructions here. As you can see, it's just made of a battery, two safety pins (which act like wires to conduct electricity from the battery to the magnet wire, but serve the added purpose of having holes for the wire to spin through!), a coil of magnet wire, and a magnet. We used clay to hold the battery in place.

I would add, to the instructions linked above, that you should make your coil of wire by wrapping it around a size _C_ battery (not D)---otherwise it will be too large in diameter to turn freely. 

You also need to make sure to only scrape off the wire coating on half of the wire's diameter. In other words, the copper wire that goes through the safety pins will only be in contact with electricity for half the time--as it spins, the coating and the wire itself will take turns contacting the safety pins. This is essentially your commutator, allowing the direct current of the battery to alternate its path into the coil and thus keep the motor spinning.

Once you get it going, it should spin on its own for quite a while, and you can stop or slow it by bringing magnets close to the coil. It's really fun to play with.

We also made an electromagnet that could pick up paper clips when the current was flowing, but not when the circuit was broken.

More motor and generator stuff:

I think I linked this elsewhere, but we liked this information on AC vs DC motors

And this is a good video on the induction motor.

This generator project looked pretty fun. (Here is our previous, ill-fated attempt at a hydropowered generator--maybe taking out the hydropower component would make things simpler and less liked to go wrong!)

Here are Abe's and Seb's diagrams of how motors/generators work:
And the one we made all together

1 comment:

  1. Thanks for the ping on the instructions! Loved reading your post - and the kids' illustrations of the generators and motors are beautiful!


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