Compare the hair dryer motor to the one you can build
About this video
This short lesson compares a homemade electric motor with a hair dryer motor. Both use permanent magnets and an electromagnetic coil that is pushed around by the magnetic force. The homemade version uses stripped copper wire and washers as its commutator and brushes, and the switch on the hair dryer simply turns the current on and off.
You'll be able to
- identify the permanent magnets, coil and commutator in a simple DC motor.
- explain how an electromagnet pushes against permanent magnets to make a motor spin.
- compare a homemade motor with a commercial one by function, not just appearance.
Key words
- permanent magnet
- A magnet that keeps its magnetism without power and sits fixed in the motor.
- armature
- The rotating coil of wire that becomes an electromagnet when current flows through it.
- commutator
- The part that reverses current direction in the coil as the motor turns.
- brushes
- Conductors that carry current from the battery into the commutator.
- electromagnet
- A coil that becomes magnetic only while current flows through it.
Transcript
- [Instructor] Alright, so here's our motor and then we talked about all of the different components in the motor and how they work, so I'm gonna try and talk about the motor that we made here and show you how it's similar to the motor that we have here, so these are our permanent magnets, so they are just like, they're behaving just like this guy, which is the permanent magnet in our hair dryer motor and they're both opposing poles, so this is north pole and this is the south pole magnet and so, if you put them next to each other, the way they're set up, they would wanna snap together 'cause the opposites attract, but those opposite poles are important, so that as the armature, which is this guy,
represented by this coil here. As that flips around, it continues to move. Now, the commutator here is actually rather hard to see, but it is the copper wire here that's been stripped, so we strip away the insulation on the copper wire on this side, but we left it on this side.
Now, the insulation is actually a clear lacquer, so it's hard to see, but we did strip that away with a knife and so that means that that section of the copper wire is functioning just like our commutator here in our electric motor and the brushes, which conducts the electricity from the contact here into the commutator, well, our washers are functioning just like the brushes, so they're conducting the electricity from our battery down to our commutator or wire and that's conducting the power through the coil or the armature and then back out the other side and back to the battery and completing the circuit and so what's that doing is that it's creating an electromagnet that is resisting the permanent magnets that are here
and causing this device to spin around and turn our fan just like this guy turns our hair dryer motor fan, so let's take a look at how that works. In our hair dryer motor, we have a switch. When we turn it on, the fan starts spinning and on this one, same thing happens, so you can see the motors spinning there and then we turn the switch off and it'll stop spinning.
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