Optimizing DC Current Through Neodymium Magnets for Efficient Power Transfer

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Discussion Overview

The discussion revolves around the feasibility and implications of passing DC current through Neodymium magnets, specifically grade N42, for use as connectors in electrical circuits. Participants explore the potential effects on the magnetic properties of the magnets and the reliability of such connections in practical applications.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested, Conceptual clarification

Main Points Raised

  • One participant inquires about the downsides of using Neodymium magnets as connectors for DC current, specifically asking about the safe current limits without affecting the magnet's magnetic properties.
  • Another participant notes that heating the magnet above its Curie temperature will cause it to lose its magnetic field, suggesting that 150mA is likely safe, but 2A depends on the magnet's size, shape, and mounting.
  • A different participant emphasizes that using magnets as connectors may not be reliable due to the need for a gas-tight interface to prevent corrosion, highlighting the importance of contact force and multiple contact points.
  • One participant shares their practical application of using spherical magnets to connect LED circuits, indicating that they are considering the current limits for potentially running multiple LEDs.
  • Another participant suggests looking at existing magnetic power connectors, like those in Apple Macbooks, and proposes using a thin layer of a good conductor on the magnets' surfaces to improve connectivity while maintaining magnetic force.

Areas of Agreement / Disagreement

Participants express varying opinions on the reliability of using magnets as connectors, with some acknowledging potential issues while others explore alternative solutions. There is no consensus on the maximum safe current or the best approach to ensure reliable connections.

Contextual Notes

Participants mention factors such as the Curie temperature of Neodymium magnets and the importance of contact interface design, but these considerations remain unresolved in terms of specific applications and configurations.

Who May Find This Useful

Individuals interested in electrical engineering, circuit design, and innovative connector solutions may find this discussion relevant.

ebaqui
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Hi

I want to pass DC current through a magnet, essentially using it as connector. The magnet I am using specifically is Neodymium (NdFeB) grade N42. The DC current I would like to pass through it is 100mA ~ 150mA (3V DC ~ 7V DC)

I would like to know if there is any downside to the magnetic effect of this permanent magnet?

Is there a way to determine how high i can go with the DC current in this situation without a noticeable detrimental effect on the magnetic effect of the magnet, like 1A ~ 2A?

Thank you
 
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Nothing special should happen. But if you heat the magnet above its curie temp it will lose all its magnetic field.
The curie temp is especially low for neodymium magnets, for some types it's only about 80 degrees C.
So 150mA would most likely be OK. At 2A it will depend on the size,shape and mounting of the magnet how much it is heated.
 
ebaqui said:
Hi

I want to pass DC current through a magnet, essentially using it as connector. The magnet I am using specifically is Neodymium (NdFeB) grade N42. The DC current I would like to pass through it is 100mA ~ 150mA (3V DC ~ 7V DC)

I would like to know if there is any downside to the magnetic effect of this permanent magnet?

Is there a way to determine how high i can go with the DC current in this situation without a noticeable detrimental effect on the magnetic effect of the magnet, like 1A ~ 2A?

Thank you

Welcome to the PF.

In addition to Jim's comments, keep in mind that what you are suggesting will not be a very good or reliable connector. To be reliable, the connection interface needs to have enough contact force to provide a gas-tight interface between the two conductors. If the interface is not air-tight, corrosion will happen in the interface (at different rates, depending on the contact material). Also, a good connector should have multiple points of contact. The surface of the magnet will be flat, with no dimples to give multiple contact points with gas-tight seals.

What is the application?
 
Jim_A said:
Nothing special should happen. But if you heat the magnet above its curie temp it will lose all its magnetic field.
The curie temp is especially low for neodymium magnets, for some types it's only about 80 degrees C.
So 150mA would most likely be OK. At 2A it will depend on the size,shape and mounting of the magnet how much it is heated.

I am currently using spherical magnets 0.25" diameter. I cut a wire and connected magnets on each end, so when the magnets come in contact the circuit of leds will turn on. The 2A is for potentially running a number of leds.

Thanks for your help on this Jim
 
Jim_A said:
Nothing special should happen. But if you heat the magnet above its curie temp it will lose all its magnetic field.
The curie temp is especially low for neodymium magnets, for some types it's only about 80 degrees C.
So 150mA would most likely be OK. At 2A it will depend on the size,shape and mounting of the magnet how much it is heated.

berkeman said:
Welcome to the PF.

In addition to Jim's comments, keep in mind that what you are suggesting will not be a very good or reliable connector. To be reliable, the connection interface needs to have enough contact force to provide a gas-tight interface between the two conductors. If the interface is not air-tight, corrosion will happen in the interface (at different rates, depending on the contact material). Also, a good connector should have multiple points of contact. The surface of the magnet will be flat, with no dimples to give multiple contact points with gas-tight seals.

What is the application?

That is an interesting point , I did not consider. The magnets are 0.25" spheres, Ni plated. I could use a magnet each for the positive and negative terminal contacts, right?

I am using this for an led circuit to light my workbench.

Thanks for your help Berkeman
 
The new Apple Macbooks have a magnetic power connector. You could take a look at one of them to see how they do it.
It strikes me that you could put a thin layer of good conductor on the surface of the two magnets, connecting your wires to them and by-passing the magnet material yet still have enough force to keep the contacts together. I'm not sure you would need to worry too much about the shape / completeness of the contacts. It's a factor in all switches and a slight radius on each pole is usually sufficient for a contact.
 

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