A simple electric motor, and a simple brushless electric motor

Here's two simple electric motors that are easy to build. They are slight variations on the common spinning coil design.  The first has the magnets spinning and uses the rotor as a switch to control the coil, the other has a reed switch which is activated by a small magnet spinning on a cardboard disc.

Materials:

•  2 x neodymium disc magnets (3/4")
•  Thick cardboard
•  28SWG Magnet wire
•  A 500ml plastic drinks bottle
•  Insulated wire (stranded)
•  2mm copper wire
•  Hot melt glue

For the reed switch version, the above plus a reed switch and a small magnet to activate the reed switch.

 

Step 1 Straighten the wire

Cut a piece of the copper wire about 150mm long, if it isn't straight, you can straighten the wire by twisting it an electric drill. Hold the other end with pliers and twist it in the drill, it should straighten it out.

Comments

[fafashizzle]

Ok thanks but also i wondering if i could use rare earth magnets and how exactly does a reed relay work?? Once again... thanks for the help

[ilpug]

Rare earth magnets are the same thing as neodymium magnets.

[fafashizzle]

Hi i was wondering for the reed switch motor if i could use normal magnets instead of neodymium magnets... your help would be appreciated

[scraptopower]

You can but don't work anywhere near as well, they are more difficult to get working. As it's for your science fair, I'm sure you want the best show.

You should be able to use the reed relay, but I can't say for sure.

[fafashizzle]

also could i use a reed relay instead of a reed switch?

[rimar2000]

Interesting. What role does the optional diode?

[scraptopower]

Yep nacho has it right.

[rimar2000]

Thanks, reukpower.

[NachoMahma]

. That diode is there to short out the spike that is generated when the magnetic field collapses in the coil when the switch is opened.

[rimar2000]

Thanks, Nacho. I envy those who know electronics.

[Kiteman]

The brushless version is quite nice. Two questions, though:

Which one has the greatest torque?

Which one has the longest battery life?

[scraptopower]

I think the first version should win on both of those, though I don't know for sure about the torgue. The brushless version has pretty poor performance all round and draws a lot of current. It's difficult to measure the current because it's pulsing and more like AC than DC, so I'm not sure that my measurements are even accurate.

Sorry that isn't too helpful or scientific!

[Phil B]

I like the version where the magnet on the spinning wheel activates the reed switch to replace the pulsing normally provided by the brushes. Otherwise, it is similar to what is sometimes called a Beekman's Motor or a Ten Minute Motor. Motors like this are fun to use for children's demonstrations. Thank you for your Instructable.