 So what in the way has leaning back on it? What is up? What is up with reluctance? I'm gonna guess get right into it today Not a lot of time to sit there and shit chat and honestly, you're not here to talk about me You're here to talk about magnetism. So before we get into the whiteboard, which I'll spend some time in Let's talk a little bit about reluctance. Last week. I talked about MMF. MMF is the Magneta mode of force So it is to magnetism what EMF is to electricity meaning that there's some sort of source pushing this stuff out Whether it's an electricity which is pushing the electrons which is getting the current flow or with MMF It's pushing out those magnetic lines of flux the phi the webers this the stuff that we're gonna talk about in greater detail next week This week. We're talking about reluctance and with the name itself. You can guess what I'm going to talk to you about It is to magnetism what resistance is to electricity. So electricity electricity so Basically, what reluctance is is the opposition to the setting up of flux lines and when we're talking about reluctance We're generally talking about the core because what'll happen is if you have a bunch of wire wrapped around something You can create a magnetic field. We'll talk about that in another video I'll go over this whole left-hand rule thing and get into great detail about that But what we have is a core and what with the core we have what's called permeability Which again is another video another time But just cold-node version it's the ability of a material to condense those magnetic lines of flux So if you have something that's reluctant then you've got something that doesn't want to set up those lines of flux air Does not want to set up lines of flux it lets the lines of flux go wherever it wants iron Loves to set up lines of flux therefore it has a low Reluctance so in this video, I'm just gonna jump around in the math a bit show you the Formulas that are being used and we're gonna kind of fart around with that and play around with it So let's jump into the whiteboard and talk about what the flux is going on with reluctance Okay, here we go one of my best drawings ever. I've got a emf here I've got a coil wrapped around an iron core Basically what I've set up here is something that could be used as an electromagnet Now this iron core is gonna have some reluctance It's not gonna have a lot of it because it actually does like taking those magnetic lines of flux and Divining them together, but it does have reluctance. So we're gonna learn how we can figure out what that is mathematically So here's the formula that we're gonna use RM which is just a fancy way of saying reluctance is equal to FM Which we learned last week is your magneto motive force or your MMF and then we have this one Phi That's basically the amount of flux lines you have and I'll talk about that more next week when I get into the Whole Phi and what what it is the webbers and all that fun stuff So as always the best thing we can do is let's throw some numbers at it and see what happens I've got let's say that I've got an MMF. I'm creating with this current that's flowing through these number of turns I'm creating 7600 ampere turns Let's say that that creates 50 webbers of flux So that's actually quite a bit of flux when you think about it because each webber has a hundred million lines of flux to it What we're gonna do is we're gonna use what we know these values to determine what the reluctance of this circuit is So what we'll do here is RM Which is what we're looking for is equal to FM Which is your 7600 divided by your webbers or 50 webbers there? That then works out to be 152 ampere turns per Weber. So that's just using the actual Formula itself. We didn't have to move anything around. We didn't have to transpose everything was easy peasy Let's see what happens here now Let's say that I've got 12 amps. I don't have the number of turns. I don't know what that is here I do know that my reluctance is 125 But I and I do know that my webbers or my Phi is 36 webbers. So what do we do? Well, we know we're gonna use this formula here. So we can use this reluctance Sorry, this reluctance and this Phi this reluctance and this Phi to figure out what my MMF is I also know that my MMF is equal to the number of turns times the amps So once I have this calculated, I can just move this over to here I don't have this but I do have the amps and I can go ahead and calculate from there So let's go ahead. We're just gonna we could also punch the number in here and we can calculate this out We did a little bit of transposing RM is equal to FM over Phi RM is equal to n times I which is just replacing that FM here with this part of the formula And I can just go ahead and plug all the numbers in as I need them So 125 is equal to n which I don't know times I which would be your FM anyways divided by 36 125 times 36 is equal to n times 12 cross multiply Then I end up getting one I need to get 12 alone. So I just divide that out So it's 125 times 36 divided by 12 gives me n and N is 375 turns that's a tricky question granted but the nice thing about YouTube is guess what you can hit pause go back and See what I was talking about and then go from there again and over and over and over again So remember I say this all the time and I will continue to say it forever Make sure you use that pause button liberally as you're watching this All right, let's figure this one out. We're gonna do it again except this time We have the number of turns, but we don't have the amps So we start with the formula that we have RM is equal to n times I over Phi or FM over Phi same thing I We just move this around a little bit and we get I is equal to There was the reluctance times the Phi is equal to and all I did was transpose to move this around I wanted to get I alone So I'm not going to go into how that all worked out But if you need help with that put something in the comments down below, I'll do a little thing up on it So I is equal to 22 times 72 divided by 880 boom I is equal to 1.8 amps and There you go that is reluctance now when we're talking about that remember that that 22 Is just telling me how reluctant this core is to the setting up of flux lines not too crazy again Everybody makes magnetism out to be way more difficult than it needs to be So there you go. It's that easy. I know I always say it's that easy and it's obviously not that easy But I can't stress enough and I said it earlier in the whiteboard Hit the pause button go back watch it again until it makes sense And if it doesn't make sense go down into the comments below I might not get back right away though I'm trying to get better at that but somebody usually does and it's a great community here at the Electric Academy So make sure you're getting that stuff in there and we'll go from there next week We're gonna talk more about that Phi what Phi is and we'll get a little bit deeper into it We'll fool around with the math as well. Have a great week. See you next Thursday. Stay classy