How Motors Work For Beginners (Episode 1): The DC Motor: 032

most people are comfortable with the idea that magnets when you turn like feels to each other for example South Pole to South Pole that they pushed against each other they repel and that's kind of what I've got here I've got the magnets alternated so that they're repelling feels while facing each other now all of these magnets come out of microwaves here are some smaller neodymium magnets which are even more powerful especially considering their size now the interesting thing that you may not know is the effect that magnets have on conductors that is like wire something like this I want to demonstrate this so let's see if I can do that I made this in a previous video and you can click on the link here to watch that one but basically this is wire I believe it's aluminum and I have called it up around a piece of iron all right I'm gonna take this magnet [Music] and as you can see we're producing a voltage I've increased the stock of Magnus to try to increase the magnetic field let's watch the voltmeter now and oh yeah so as you can see when a magnet passes by a wire current starts to flow as indicated by the voltage so there are three things that you need in order to have this effect one you need something that produces a magnetic field you need a conductor and you also need relative motion if I just sit the magnet here there's no voltage but when the magnet is moving as you can see there's a voltage being produced I have one more example I want to show you that demonstrates this principle alright so we got our battery hooked up and when I turn this on as you can see it's producing a magnetic field that magnet started moving and there you go it's now a magnet or it was it's gone no magnetic field but it was so powerful it actually pushed that magnet away way over there that was pretty impressive actually let's try that again all right let's see the compass needle right now it's aligned with this magnet but as you can see and if you watch that neodymium magnet over there [Applause] so there you go when you run electricity through a wire it produces a magnetic field when the magnetic field passes a conductor that conductor itself becomes a magnet as we saw earlier in the magnetic field that's produced by that conductor opposes the magnetic field of the magnet that's going by another way I want to demonstrate this I'm going to take this neodymium magnet here and drop it inside of this copper tube and let's see what happens in fact I'm going to use my phone to videotape this so we can have two perspectives while the magnet is passing through the copper tube the copper tube itself is becoming an electromagnet in the region right around the magnet and the magnetic field is opposing the magnet which is slowing down the descent now just to prove you that is not friction or anything like that I've got a larger copper tube let's try that one and it falls a little bit faster because the magnet is further away but it's the same idea but if you need use something that doesn't conduct at all then you get what you would expect the magnet is false so how do we turn this magnetism and electricity into something useful when I'm pretending like this is a shaft and we'll use this threaded rod to give us something to rotate about okay now we already know that the magnets attract and repel each other right but what if we could rotate the magnetic field around the shaft then the magnet on the inside would follow it right or you can make them repel as well like that by simply turning to the opposite side but doing it this way is not all that efficient right what if there is a way to move the magnetic field electrically well that's basically what the commutator does so I think we're ready to talk about that guy first let me describe the parts that we have here this is called the stator and inside a permanent magnet motor there are two permanent magnets you could reverse this the magnets could be here on the rotor and then you could put windings here and then rotate to fill electrically in fact that's basically how a brushless DC motor works but we'll probably talk about that some other time in this event we've got a permanent magnet here in here a north and a South Pole and this is what's called the stator field this is where the the magnetic field is produced by two permanent magnets and because this part is stationary it's called the stator field here we have the rotor you see that there's a whole bunch of laminated plates and they seem to be all glued together these are all sheets of iron there's a reason they use sheets instead of making it out of one solid piece but this is a beginners video so we're going to save that for another time but basically they laminate all these pieces together and that helps to enhance the magnetic field like I showed you earlier and you can see what should look familiar to you coils of wire wrapped in between these loops then I'll show you on this one over here you can see the same thing coils of wire loop inside the iron slots here each one of those coils come down and touch this guy which is called a commutator so you'll have one bar on this side and then directly opposite of that you'll have the other bar that touches one of these coils and so when you touch those two ends of ledger glass like so you energize that coil and it becomes an electromagnet all right now we're getting to the meat of it so we have a magnet down here just like we have a magnet in the stator what will happen when I energize this here in a little bit one of these coils is going to be electrified it'll become a magnet with a north and a South Pole and it will want to align itself with the magnetic field down here at the bottom and it'll begin to rotate but these guys over here these are this is a brush assembly and these are carbon brushes and let me take that out and show it to you and then I'll tell you how it works all right you can see there's a copper wire there and this is where these two wires that come out of the back they come in and touch these two brushes so one wire is going down here and one wire is going here this is what supplies electricity to the rotor as you can see that there's a spring here in this case you've got a material that's both conductive and you can push it with this spring that'll keep contact with this commutator while is rotating you know at 4,000 revolutions per minute so that's basically what this does this supplies current to the rotor and helps to turn our rotor here and specifically our individual coils into electromagnets when that first coil starts to rotate the shaft the brush will then start to touch the next two coils and it's kind of like a squirrel running in a cage as he steps on each rung the cage is moving under him instead of him actually progressing forward and that is what's happening at least electrically the electro magnetic field is always displaced from the permanent magnet and so it's constantly chasing that whatever energy you can produce there can be put out at the shaft here let me put this back in and let's wire it up over here I've got my 1200 battery and I've got a switch wired in between that just makes it so I don't get a big spark every time I'll hook this up to the battery all right let's see what happens [Music] okay don't get too excited yet we're gonna turn it back on a couple things I want you to notice number one it's rotating towards me I'm just gonna flip this over this is my South Pole and I've indicated my North Pole right there and now you can see it's spinning the other way so it's it's a really neat notice one more thing I want to show you now and now that I've got current flowing through a bit note magnet you can see there's a North there it is and a South Pole I see that one more time I love this thing so anyway there you have it electromagnetism and this is the permanent magnet and DC motor hopefully you found that helpful let me know in the comments if you have any questions if I've made any mistakes or omitted anything I will add comments to the description so be sure to check that I do intend to talk about the three-phase motor the other induction motors the universal motor and there'll be videos like this if you want to be notified when the next video comes out just hit the subscribe button that'll come on right here I'll put a couple more videos up here so you have something to watch while you wait and until then thanks for watching

Channel: Jeremy Fielding

Views: 2,552,428

Keywords: How do motors work, parmanent magnet DC Motor, what is electromagnetism, how do magnets make electricity, What are the types of motors, electric motors

Id: onjFFoOC_yk

Length: 11min 46sec (706 seconds)

Published: Mon Jun 26 2017