{"id":68560,"date":"2026-10-18T05:01:17","date_gmt":"2026-10-17T20:01:17","guid":{"rendered":"https:\/\/phys-edu.net\/wp\/?p=68560"},"modified":"2026-10-18T05:01:17","modified_gmt":"2026-10-17T20:01:17","slug":"we-took-apart-a-motor-and-found-just-a-coil-and-a-magnet-the-secret-behind-the-spin","status":"publish","type":"post","link":"https:\/\/phys-edu.net\/wp\/?p=68560&lang=en","title":{"rendered":"We Took Apart a Motor and Found Just a Coil and a Magnet! The Secret Behind the Spin"},"content":{"rendered":"

Ken Kuwako, Science Trainer. Every day is an experiment.<\/strong><\/span><\/p>\n

I took a motor apart to see what was inside. I was sure there’d be some complicated machinery in there, but all I found was a coil and a magnet. Just those two things. And yet they power electric fans, electric cars, and even drones.<\/p>\n

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So what’s actually inside a motor?<\/h3>\n

The magnets were stuck to the inside of the motor’s outer case. The coils were wound around an iron core. And I could clearly see the metal commutator, too.<\/p>\n

In other words, the magnets sit still on the outside, while the iron core wrapped in coils spins on the inside. When electricity flows, the coils turn, and that spinning motion is carried out through the motor’s shaft.<\/p>\n

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The force on a current in a magnetic field makes it spin<\/h3>\n

This motor shows off the principle beautifully: a motor spins because of the force that a current feels in a magnetic field. Run a current through a coil sitting inside a magnet’s field, and the coil gets pushed. The current flows in opposite directions on the coil’s right and left sides, so the forces point in opposite directions too, and together they twist the coil around.<\/p>\n

You can work out the direction of that force with Fleming’s left-hand rule, which you may remember from junior high science. That diagram in your textbook? Here it is, working in real life.<\/p>\n

The commutator: the part that flips the current<\/h3>\n

Now enter the commutator. If the coil simply kept turning, then after half a rotation the force would reverse and the spinning would stop dead. So at just the right moment, the commutator flips the direction of the current flowing through the coil. That way, the coil keeps getting pushed the same way and can keep spinning.<\/p>\n

Reversing the current mid-rotation. That one clever trick is the heart of the motor.<\/p>\n

A paper clip motor has just one coil. Because of that, there are spots where it tends to get stuck (positions where the force can’t do its job), and sometimes it won’t start unless you give it a little flick with your finger first.<\/p>\n

This motor, on the other hand, has three coils wound around its iron core. As it turns, the commutator keeps switching the magnetic poles of the three sections of the core, one after another. So no matter what angle it’s stopped at, there’s always a force pushing it to rotate. That’s why it starts up all by itself the moment current flows. If you’ve ever played with a paper clip motor, this “it just goes on its own” magic will really surprise you.<\/p>\n

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