Quxk electromagnet help

[Njguy]

Quick electromagnet help

I may be missing something obvious, but are dipole electromagnets always far weaker than parallel pole magnets(not sure if that's the proper term)? I have noticed that the average 6 watt parallel pole electromagnet will generate around 100-125lbs of holding force, or power (my observation comes sales charts for electromagnets). Now a similar sized dipole electromagnet running on 6 watts seems to be lucky if it can hold 10 pounds.

It doesn't seem to make much sense to me that just because your making use of both poles, the power of the electromagnet jumps by an order of magnitude. Around 10X here. Any thoughts?

 

[Njguy]

Sorry about the title, it's supposed to say Quick.

 

[Sceadwian]

You can edit the original post topic using the advanced editing features in post editing. I've done before.

It probably has to do with the way the coils are wound. I've never actually seen a parallel wound coil, but normal solenoid wound coils have a lot of mutual inductance between each coil so for the same current the magnetic field will be stronger. Their physical construction is dramaticaly different.

Could you post a link to a parallel wound coil? I'm curious.

 

[Njguy]

You can edit the original post topic using the advanced editing features in post editing. I've done before.

It probably has to do with the way the coils are wound. I've never actually seen a parallel wound coil, but normal solenoid wound coils have a lot of mutual inductance between each coil so for the same current the magnetic field will be stronger. Their physical construction is dramaticaly different.

Could you post a link to a parallel wound coil? I'm curious.

I have no idea how they are wound, I would love to know myself. The best I can give you is a link to a place that sells them.


https://www.electro-tech-online.com/custompdfs/2010/01/Round-12-24-Volt-DC.pdf

 

[unclejed613]

you need to magnetically couple the top poles of the coils to get a dipole magnet. kind of like an electric horseshoe magnet.

 

[Njguy]

you need to magnetically couple the top poles of the coils to get a dipole magnet. kind of like an electric horseshoe magnet.

I don't think you mean the dipole. Dipole I was told is North on one end and South on the other.

 

[Sceadwian]

Niguy... All magnets are dipoles. Yer using some confusing confusing terminology. there is no such thing as a parellel pole magnet. You're only refering to dipole and parallel pole in relation to a cylindrical shape. So like I said, not sure what you're talking about as I've never seen a cylindrical electro magnet that is magnetisezed in that manner. I do know that we use rod magnets as an permentant magnet filter on the sandblast cabinet we use at my work, but those are alternatly north and south faced magnetic domains imparted parallel to the walls of the magnet.

Which two units in that PDF are you comparing?

 

[Hayato]

I believe he means by "parallel" is to place the two magnets side-by-side.

You have the sensation of a stronger field because "magnectic area" is larger than when you connect your magnets by the ends.

 

[Njguy]

No that's not what I mean, my description is quite specific.

 

[Njguy]

Not all magnets are dipole. And the the electromagnets in the pdf are magnetized like my drawing, the parallel one. In a cylinder electromagnet, dipole means one pole per flat face. The ones in the pdf have two poles per flat face. It makes them super strong. I was wondering why.

 

[Sceadwian]

Njguy. ALL magnets are dipoles. They have two poles, a north and south.
When you're referring to parallel magnets you're referring to north and south being paralle with the side of the cylinder. This does NOT mean the magnet isn't still a dipole, it's just not axially magnetized. You're using the wrong terminology. As near as I can tell all the magnets in the PDF you linked are axially polarized, I have as yet to see a link to what you refer to as a parallel magnetized magnet. I do know as permanent magnets they exist as I said before the magnetic field on our sand blast cabinet is magnetized paralell to the sides of the cylindrical tubes that make up the magnet.

 

[Njguy]

Njguy. ALL magnets are dipoles. They have two poles, a north and south.
When you're referring to parallel magnets you're referring to north and south being paralle with the side of the cylinder. This does NOT mean the magnet isn't still a dipole, it's just not axially magnetized. You're using the wrong terminology. As near as I can tell all the magnets in the PDF you linked are axially polarized, I have as yet to see a link to what you refer to as a parallel magnetized magnet. I do know as permanent magnets they exist as I said before the magnetic field on our sand blast cabinet is magnetized paralell to the sides of the cylindrical tubes that make up the magnet.

Yes well I can assure you these magnets are not axially polarized. They have 2 poles on both flat faces. North and South. I did not make up the term dipole, it was given to me by an electromagnet company who sent me an email for "Dipole electromagnets, which they described as one pole on either flat face. What your arguing is irrelevant, and half wrong at best. I have yet to find an axially polarized electromagnet using 6 watts with over 100lbs of power. I dare you to try.

 

[unclejed613]

i looked closer at the drawing in the first post., and the proper terms are coaxial magnet and axial magnet. the coaxial magnet is similar to a horseshoe magnet because the S pole is looped around and brought in close proximity to the N pole of the magnet. in simple terms the magnetic lines of force are concentrated in the small circular gap between N and S. the axial magnet has the same lines of force, but they are spread out over and around the whole body of the electromagnet, and so don't provide the same amount of holding force.

 

[Njguy]

i looked closer at the drawing in the first post., and the proper terms are coaxial magnet and axial magnet. the coaxial magnet is similar to a horseshoe magnet because the S pole is looped around and brought in close proximity to the N pole of the magnet. in simple terms the magnetic lines of force are concentrated in the small circular gap between N and S. the axial magnet has the same lines of force, but they are spread out over and around the whole body of the electromagnet, and so don't provide the same amount of holding force.

Alright, thanks for the terminology. I'm just curious as to how they actually wire it. So horseshoe magnets generally speaking are stronger because they make use of both poles.

 

[Sceadwian]

You could ask the company for an internal diagram of one of their magnets, there's a slim chance they'd allow you to see it. Just say you want to know the internal structure a little better so you can better characterize the forces on the load, if you sound technical about it they might be nice enough to share =)

 

[MrAl]

I may be missing something obvious, but are dipole electromagnets always far weaker than parallel pole magnets(not sure if that's the proper term)? I have noticed that the average 6 watt parallel pole electromagnet will generate around 100-125lbs of holding force, or power (my observation comes sales charts for electromagnets). Now a similar sized dipole electromagnet running on 6 watts seems to be lucky if it can hold 10 pounds.

It doesn't seem to make much sense to me that just because your making use of both poles, the power of the electromagnet jumps by an order of magnitude. Around 10X here. Any thoughts?

Hi there,

If i understand your question correctly, you want to compare the total force at the end of two
magnets, one made by "paralleling" two and another made by putting them end to end in "series".
You have noticed that the 'parallel' method makes a magnet that is stronger than when in 'series'.

One of the things about magnet force is that it decreases over distance. That's why distance is in
the denominator of many formulas involving a magnetic force. This means that the longer the
distance, the weaker the force. When you put two magnets in 'parallel' you get more strength
then when you put them in 'series' because the distance from say the center of the magnet to the
work surface is much shorter than when they are in series, simply because the length is longer
and the magnetic core material is the same in both magnets.

For electromagnets it also depends on how you wire them together. Wired in parallel they should
be stronger because in series they have together more resistance and that means less current
and that means less force.

Also, are you sure it is actually 10 times the strength, or is it more like 4 or 8 times stronger or
something like that, and if so, where did you get that data? For a really rough calculation, two
magnets in parallel would have about 1/2 the distance as the two in series, and also would
have twice the contact area, so those taken together might give us 2^2*2 times more strength
(which is 8 times that of the series combination).

 

[Njguy]

You could ask the company for an internal diagram of one of their magnets, there's a slim chance they'd allow you to see it. Just say you want to know the internal structure a little better so you can better characterize the forces on the load, if you sound technical about it they might be nice enough to share =)

I had a hard enough time just trying to get them to show me where North and South was.

 

[MrAl]

Hi again NJguy,

You must have missed the post just ahead of yours...it was asked of you if it was really 10 times more force or more like 4 or 8.

 

[Njguy]

Hi again NJguy,

You must have missed the post just ahead of yours...it was asked of you if it was really 10 times more force or more like 4 or 8.

When I said 10 times I was generalizing, but that is around what I have seen. Axially polarized electromagnets(one pole per flat face) usually have less than 10lbs of holding force while for the same amount of electrical power co-axially electromagnets appear to have 100+ pounds of holding force. I chose 6 watts for my example. I got the data from surfing sales charts.

 

[Njguy]

I updated the drawing with proper terminology.