VERY POWERFUL MAGNETS… THE EASY WAYJun 09, 2021
Hi, a couple of months ago we posted a video on extreme
magnets, we basically went over the principles behind strong permanent
magnetsand built a large magnetic set that we use for strong magnetic fields in the lab and I have built several magnetic sets and I prefer the type of permanent magnet because they are more convenient, they have no power supply and because they are
verystable, the power supply does not introduce electronic noise. Now, if you look at a moderate strength magnet, this is a neodymium one. -Iron-boron magnets classified in n42. You can see that when I put a probe on the surface of the magnet you will get a field strength of about 250 Militello tests or 1/4 Tesla.
You will also write it down on the meter. that as I lift the probe even a couple of millimeters from the surface, the field intensity decreases
veryquickly. The reason for this is that the field lines on the surface of this magnet are being attracted towards the opposite pole and so on as you move. Far from the surface of the magnet, the merging or moving away of the field lines causes the field strength to decrease very rapidly. Now there is a trick that you can use to increase the intensity of the field, which is called a gap magnet, essentially identical to the magnet that I just showed you, but in this particular magnet we have two magnets facing north and south, so that want to join together, but we keep them apart with a small aluminum spacer to form a gap now if you look at the field intensity in In this magnet you can see that the field intensity is almost double, almost 500 Militello or half a Tesla and it is a lot more homogeneous as I move the probe back and forth, you can see that it doesn't change much as I do this and that is very convenient for a lot of research that we are doing now, the reason is that the two magnets act to isolate or isolate the effects of that scattering magnetic field coming from the opposite poles and moving the field lines away from the gap if If you want to create an even stronger magnet, you can use stronger magnetic materials here.
I have a larger space magnet that was made for a video we recently filmed during the duration. In this case, I'm using n 52 magnets and if you look and I show you the strength, you can see that on the surface of this strongest magnet we have a field of about 1/2 Tesla and you can see that the field strength tends to decrease further. slowly as I move the probe away. Two reasons for that is a stronger magnet, but the other reason is that the dimensions of the magnets are larger, so the dispersion or extension of the field lines occurs more gradually, so we have a more homogeneous magnetic field within a short distance, furthermore, if I place the probe in the gap, you can see that once again the field line, the field intensity increases in the gap between the two magnets, now it is about three quarters of a Tesla, if If you want to be even stronger, it is possible due to the maximum magnetic potential of these N52.
The magnets are about 1.4 Tesla, but to get an even stronger field, what we have to do is try to further isolate the field that attracts the weight and goes to the other pole, and the way we can do that is by using a Ferromagnetic material or steel to guide those field lines and hide them from the field that interests us within space. The other advantage of using it is that these very
powerfulmagnets are potentially very dangerous even at a distance of about 15 centimeters. It pulls tools, bolts and nuts to the surface and makes it a bit dangerous to keep one of these around.
Now the trick to doing this is to add a magnetic guide yoke material that can guide and hide those field lines. However, there is a property called saturation and steel can only hold so much field strength or essentially hold so many field lines and in these most
powerfulmagnets of all, the m-52, that amount of guiding capacity or that saturation point is similar to the strength of the magnet, so if I have a 2 inch by 3 inch Magnet, five centimeters by 7 points. 5 centimeter magnet essentially 6 inches square. I need about 6 square inches of cross section in my steel to guide the field around the yoke now, if you watched the other video and I've certainly been challenged with this: when you take quarter ton magnets and you want to take six inch blocks of steel and approximate them, it's a pretty sketchy operation, so it occurred to me that it would be something interesting if we could add that metal slowly or more gradually and I came up with what I think is an interesting approach to do.
I need to add some additional components to this magnet to make this a little easier to make, so let me do that right now. The principle here is that what I've essentially created is a sort of spool of wire and the idea is that I'm going to add, instead of four huge blocks of steel, I'm going to slowly wrap steel wire around the magnet adding the magnetic yoke to As we go, it doesn't matter that it's not a solid piece of material, I simply need a cross-sectional area. Now I came up with the idea of using 20 gauge wire simply because I wanted something thin enough to wrap around. sure, so it's not so thick that it won't fit this school, but it's also not so thin that I'd be spinning this thing for days, however, I'm still going to have to put about 1,200 turns of this steel over here and that would take a long time. time so I built another set to make it a little more convenient some tips stainless steel rod stainless steel nuts aluminum washers everything around the magnet assembly is not magnetic the metal is kept away so nothing is attracted to this very dangerous magnet .
I could have done this on the lathe, but the problem is that there are metal shavings that could be attracted to it and that would be a bit unpleasant. Plus, this powerful magnet next to a big piece of steel is kind. of a slightly incomplete assembly, very simple, you can assemble and disassemble it whenever you want and now, to wrap this, what I'm going to do is put on a pair of gloves. I'm going to have my son stand behind me to hold the spool of wire and we're going to start feeding this now remember the field when we started was about three quarters of a Tesla inside this space, let's see if adding a Steel guide for the field lines will have an improving effect on the strength of the field in there, so now let's start the wrapping.
I didn't tighten them enough. I should probably tighten them a little. a bit ok, hope that helps getting back to work, it's a lot easier to use the tools now. Alright, moment of truth, let's see what happens here, so we gain about 35%, maybe a little more than 40% in field strength here by putting the yoke over here is still not 2 1 Tesla. I'd like to see it, but it still obviously makes it stronger, and secondly, what's probably just as significant is that it doesn't pull very hard, the tools aren't drawn to it as strongly. and is therefore much safer to have in a workshop, so not a bad way to do this very convenient method of creating a yoke.
You could use even more wire and eventually that field on the outside would disappear completely and we would probably get to about a 1.05 Tesla, but this is safe, convenient and
easyand I will be doing this from now on so I hope it was useful and interesting and I want to thank you very much for watching, please subscribe because it always helps the channel and you have a wonderful evening
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