Discover the Power of Magnetic Locks: 650-1000 lbs of Force

[arydberg]

Today I just learned the concept of magnetic lock.. where pure electromagnetic force was used to lock doors.. My experience with magnets shows you can still pull two magnets apart.. but for magnetic lock.. there is no moving part, the door is closed just by the turning the electromagnets on and it is just small pieces and small voltages.. so powerful stuff! Specification says 650 lbs to 1000 lbs of force. Would anyone know the electrical patterns the magnetic lock make compared to ref magnets? How could something so small able to hold or pull 1000 lbs?

This may help,
https://www.mcmaster.com/#electromagnets/=17m1fk0

 

[oquen]

This may help,
https://www.mcmaster.com/#electromagnets/=17m1fk0

Thanks. I want to see the schematic of the coiling inside a magnetic lock. The other day when I went to a convention, I brought the lock to see how it would look like when it passed thru x-ray machine similar to that used in airports:

It didn't show any details.. just one solid rectangular block.. so if anyone in the future find a schematic.. just share it here. I bought the magnetic lock for $50 and it would be a waste to burn the plastic away.. and I'm fast losing interests in all this anyway. So I may just resell it to get back the $50. Thanks and would appreciate so much anyone in the future who could provide an internal details of the coiling of such electromagnet locks.

 

[NTL2009]

I'm pretty sure the schematic is... a coil of wire.

You seem to be looking for magic. I think this is simply a coil of wire around a pole piece. I'm sure there are some specifics to the design of the pole piece to optimize the force where they want it, but that's all.

Did you do the calculations of current and forces and determine how many turns would be required for that force? Will a wire of that current capability fit into that space with that many turns? Bring that calculation back to the forum, and I think you will get your answer. Hint: for the calculations I found, all else equal, the magnetic force is directly related to the number of turns (in theory - there will be practical matters that influence that).

http://spiff.rit.edu/classes/phys213/lectures/amp/amp_long.html

 

[oquen]

I'm pretty sure the schematic is... a coil of wire.

You seem to be looking for magic. I think this is simply a coil of wire around a pole piece. I'm sure there are some specifics to the design of the pole piece to optimize the force where they want it, but that's all.

Did you do the calculations of current and forces and determine how many turns would be required for that force? Will a wire of that current capability fit into that space with that many turns? Bring that calculation back to the forum, and I think you will get your answer. Hint: for the calculations I found, all else equal, the magnetic force is directly related to the number of turns (in theory - there will be practical matters that influence that).

http://spiff.rit.edu/classes/phys213/lectures/amp/amp_long.html

I know an electromagnet is simply a coil of wire around a pole piece. The specific of how they can just make one surface magnetic while all the other sides are not magnetic is what I'd like to know.. like how they optimize it. that's all.

 

[NTL2009]

I know an electromagnet is simply a coil of wire around a pole piece. The specific of how they can just make one surface magnetic while all the other sides are not magnetic is what I'd like to know.. like how they optimize it. that's all.

It should be fairly obvious if you have ever played with a magnet and a piece of iron. From wiki, iron (depending on composition) can have thousands to hundreds of thousands higher permeability than air:

https://en.wikipedia.org/wiki/Permeability_(electromagnetism)#Values_for_some_common_materials

So that magnetic field is contained almost completely to the pole piece. I've got some strong magnets from hard drives that are mounted on a metal plate. Super strong on the magnet side, but it won't even hold a paper clip on the other side of the metal piece. I'm sure you can find some web sources discussing electromagnets and their pole pieces and how they are adapted for different purposes.

I think it's time for you to do some reading and research on your own, rather than coming here for answers.

 

[oquen]

It should be fairly obvious if you have ever played with a magnet and a piece of iron. From wiki, iron (depending on composition) can have thousands to hundreds of thousands higher permeability than air:

https://en.wikipedia.org/wiki/Permeability_(electromagnetism)#Values_for_some_common_materials

So that magnetic field is contained almost completely to the pole piece. I've got some strong magnets from hard drives that are mounted on a metal plate. Super strong on the magnet side, but it won't even hold a paper clip on the other side of the metal piece. I'm sure you can find some web sources discussing electromagnets and their pole pieces and how they are adapted for different purposes.

I think it's time for you to do some reading and research on your own, rather than coming here for answers.

All my magnets since a child were small so I thought they equally attract iron at all area. So it's only the pole. Now the videos in youtube makes sense why the fillings where only attracted to the poles (I thought they just did it that way). Thanks for mentioning permeability. Everything finally makes sense. It's good you mentioned it or I could have missed that concept.