New King of Magnetic Power? | Electromagnet vs. Neodymium Magnet

After playing and experimenting with permanent neodymium magnets for over a decade, it is time to take the first steps into the world of electromagnets!
In this initial video, I will run some basic tests and compare it to a neodymium magnet of similar size. Will I like the electrical version of magnets?

The F71 Teslameter donated earlier by Lake Shore Cryotronics:

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#Electromagnet #PermanentMagnet #Brainiac75

[CodeParade]

You should give superconducting magnets a try. You won't have to worry about heat or any power loss, just need a good source of liquid nitrogen. Would love to see your detailed analysis of one!

[LabCoatz_Science]

Could we all just take a moment to appreciate the quality put into these videos? Truly amazing, keep it up man!

[DrakkarCalethiel]

Overclocking an electromagnet and colling it with an AIO. Are we now at LTT? 😆 Biggest gains on that magnet would come from cooling it down with LN2.
Would be a great vid, temperature vs magnetic strength vs power draw. With that tesla meter of yours, it would be very interesting to see that curve!

[izzieb]

The truly strongest form of magnetism is produced by your enthusiasm for magnets. It's what keeps attracting people back to your channel.

[jetseverschuren]

The magnetic strength doubling with a 4 fold increase of wattage is logical. The field strength is linear with the current, and the current is linear with the voltage. Since P=I*U and I and U both increase linearly with the field strength, the power (wattage) increases quadraticly (or the magnetic field with the root of the power). To combat the heating issue, set your power supply to "unlimited" voltage, and limit the current, then the field strength will stay constant (even though it still heats up a lot)

[GQuack]

Electromagnets are interesting in their own right, though happy to hear that passive neodymium magnets beat them out in some cases! Great video as always.

[BlackHoleForge]

That was such a good safety tip. I would have never thought about needing a UPS for your lab bench power supply.

[brianperreault]

I'm an engineer that designs linear motors with permanent magnets. Your testing of the open air magnetic field does not represent the lifting power of the electromagnet. If you put the electromagnet against a flat piece of steel with a gauss meter in between, you would measure a much higher field. Note that the steel plate should be thick to get the highest measurements (10 mm thick is probably enough). With the electromagnet in the open air (no steel plate), the magnetomotive force must be distributed across the air gap between the center circular pole and the outside ring pole. If you put those poles against against a flat steel plate (steel has high permeability), the air gap is much smaller, and you will end up with a much larger field (probably around or over 10000 Gauss, approaching the saturation point of the steel pole in the center). When you use the neodymium magnet against a steel plate, it's large magnetomotive force is mostly spent creating a magnetic field across its own (low permeability) interior -- its own material acts much like an air gap. It's magnetomotive force is so high, however, that it can create high forces.

I would suggest that you perform a lifting test with the two magnets, and see how much weight you can lift with each one. Hang your magnet from a strong support with the poles facing down on the electromagnet (it looks like the electromagnet may have threaded holes for this purpose). Stick a thick (1 cm or more), flat piece of steel to the bottom of the magnet. Add weight to the steel until it falls off. That will give you a much better idea of the lifting capability. Repeat with the Neodymium magnet (You will likely have to use a clamp to hang the Neodymium magnet, or you can just stick it to the bottom of a thick steel beam or plate).

The electromagnet will have high attractive forces with a small gaps, but the force will fall off quickly with increasing gaps. The Neodymium magnet's forces will fall off more slowly with increasing gap.

When performing the same test with a thin sheet of steel, the sheet of steel will saturate (it has high permeability for only about the first 20000 gauss, and then saturates), and you will get much lower attractive forces.

Good luck!

[bubba]

A lot of times when stuff is advertised as "12V" they actually mean something more like 14V because that is the kind of voltage it would actually see in an automotive application and most 12V applications are automotive. Could explain some of the wattage discrepency.

[protocol]

The electromagnet has the advantage of metal cup to close (concentrate) the magnetic circuit. If you gave the neo magnet a similar cup it would increase its holding force, further increasing its advantage. A lot of fridge magnets do this so they can use cheaper ceramic magnets that wouldn't hold without the cup. flexible sheet magnets do something similar by alternating polarity in stripes.

You should also look at switchable permanent magnets as they have feature parity with electromagnets.

[InssiAjaton]

Your electromagnets brought some memories. When I first got to deal with the math of electromagnets, I decided to try some optimization of my own. To my frustration, the math "converged" always to the lowest number of wire turns, using heavier and heavier gauge wires. In fact, my end result was that a single turn of wire that filled the whole available volume always produced the highest magnetic flux with least resistive heat. Of course, the flux density is determined by the air gap, as long as the core does not saturate. Your probing showed well below my usual assumption of 1.2 T (tesla = 10 000 gauss) to 1.5 T field density saturation for ordinary magnetic core materials. So you would be able to push beyond the neodymium field density with a single turn winding and maybe 0.1 V / 200 A supply without excessive heating, if you can provide such a supply. (0.1 V x 100 A = just 10 W).

[wolfrobots]

your videos are premium in pace, edits and narration....i love them

[Quickened]

Magnets happen to be one of my favorite subjects. I believe if the core were taken out and shaved to half its diameter, and then rewound with more windings, you could potentially double the gauss output with the same volume. Can't wait to see you build some of your own! Imagine the ones they use in wrecking yards to lift entire cars, the possibilities are endless.

Speaking of turning on and off, I have seen some permanent magnet gadgets that turn on and off the magnetic field by flipping a lever. What's that all about? Great video!

[flappingflight]

There is a trick with electromagnets, which allows you to reach higher pulling force than any permanent magnet is able on , without overheating of the coil .
By the way the strongest magnetic fields are archived by electromagnets !

[sophiophile]

You can get "switchable" permanent magnets as well, where you turn something on top to change the positioning of two magnets to cancel eachother out in the off position. (I'm sure you know this, but since you mentioned the ability to turn off as the main advantage I thought I'd add this comment)

[TigTex]

Please don't say "overclock" when you are only changing voltages and currents to values out of spec. The correct term is "overvolt"
Having said that, I've enjoyed the video! Let's see what the future brings for that little magnet-on-demand! Cheers

[milespeterson]

I love making those little homemade bolt electromagnets in fact, If you give the electromagnet more current it will get hotter. More Voltage = More Strength | More Current = More Heat. I even tried to make an electromagnet oven by giving it around 5v DC 2 amps. this gave the magnets a fair amount of strength. but they got very hot. I was almost able to make toast with my oven! They even have induction cookers that are just a giant electromagnets with lots of current. It's fun to experiment with this kind of stuff! keep it up Brainiac75!!

[ChrispyNut]

Just started binge watching this channel a few videos ago. Looking forward to seeing the progression up the liquid-> water -> sub-ambient -> L2N goes, as the colder it run, the better it runs.

[AppliedCryogenics]

I love this channel so so much. Thank you, Brainiac75!

[markylon]

Great video, When I was younger I used to work for a company that had an electro magnetic lock on the door. During office opening hours the door was propped open and the magnet was at the top of the door frame. For fun we would turn the lock on and put some paperclips on the magnet. Then when someone walked through the door we would turn the magnet off as the paper clips dropped on their head. It was harmless fun as we watched from a distance as the bemused person wondered where the paperclips came from. This would amuse us for hours.