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I have a setup for one of my robotics projects where a neodymium magnet is placed across from an electromagnet. I power the magnet with DC through a L298N motor controller that is connected to an Arduino.

Will my neodymium magnet attract the electromagnet across from it when there is no power being supplied to the electromagnet? I know that the electromagnet has a somewhat magnetic core.

My goal in this setup is for the neodymium magnet to not be touching the electromagnet until power is supplied to the electromagnet, then they can attract. I do not want to repel with the electromagnet, thus why I am asking this question.

Basically I have my electromagnet attached with a 3d printed stick to a gear, and a magnet (at the moment before I asked this question) positioned stationary across from that electromagnet (the angle is not straight but close to straight). What I would like to do is when the electromagnet is given power, it will attract towards the stationary magnet and turn the gear

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    \$\begingroup\$ the force between the magnets and whether they touch are different questions. The latter is a mechanical question, how are they mounted, with what degrees of freedom? \$\endgroup\$
    – Neil_UK
    Jul 20, 2021 at 13:32

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A non-energised electromagnet is also known as a 'lump of soft iron'. A permanent magnet will attract a lump of soft iron.

If you energise the magnet slightly, it will increase or decrease the pull from the permanent magnet, depending on the direction of magnetisation. At some distances and energisation currents, you may get zero force.

If you want there to be zero force between permanent magnet and electromagnet, then it needs to be air-cored, not iron-cored.

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  • \$\begingroup\$ In order to achieve my behavior, what would be a smart replacement for the Neodymium magnets to be able to be attracted but not to attract the electromagnet? Low magnetism magnets (like fridge magnets etc.)? \$\endgroup\$
    – Cousin Ale
    Jul 20, 2021 at 13:31
  • \$\begingroup\$ @CousinAle What behaviour do you want? It's not clear. \$\endgroup\$
    – Neil_UK
    Jul 20, 2021 at 13:33
  • \$\begingroup\$ Basically I have my electromagnet attatched with a 3d printed stick to a gear, and a magnet (at the moment before I asked this question) positioned stationary across from that electromagnet (the angle is not straight but close to straight). What I would like to do is when the electromagnet is given power, it will attract towards the stationary magnet and turn the gear. \$\endgroup\$
    – Cousin Ale
    Jul 20, 2021 at 13:36
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    \$\begingroup\$ @CousinAle In that case, you might be better off with a lump of soft iron instead of your permanent magnet. That way, you'll have no force when there's no current, and force when there's current. I've taken the liberty of putting your explanation into your question, as comments tend to not get read by other visitors, or get deleted sometimes. Putting it in the question maximises the chance that you'll get other answers. \$\endgroup\$
    – Neil_UK
    Jul 20, 2021 at 13:53
  • \$\begingroup\$ One more question, I cannot find really any product for soft iron that I can buy online, would these ceramic magnets be such low strength that they would work instead of an iron core? I think the material is ferrite not sure. amazon.com/Craft-Magnets-Ceramic-Refrigerator-Whiteboard/dp/… \$\endgroup\$
    – Cousin Ale
    Jul 20, 2021 at 15:04

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