Moving magnetized objects apart

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Discussion Overview

The discussion revolves around the concept of moving magnetized objects, specifically a steel plate, away from a magnet. Participants explore the possibility of inducing an electrical current to reduce the attraction between the steel plate and the magnet, as well as the implications of repeated applications of this method on the magnetism of the steel plate. The scope includes theoretical and practical considerations related to magnetism and electromagnetism.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant inquires whether an electrical current can be induced in a steel plate to reduce its attraction to a magnet, likening it to the reverse of activating an electromagnet.
  • Another participant suggests that using coil windings around the magnet to drive a current could potentially nullify or reduce the magnetic field affecting the steel plate.
  • There is a question about whether repeated applications of this method would lead to a permanent reduction in the magnetism of the steel plate, with reference to the B-H hysteresis curve of the magnetic material.
  • A participant mentions that magnets can do work on objects through mechanical work and energy stored in the magnetic field, highlighting the complexity of the relationship between magnetic fields and work done.
  • One participant asserts that it is not possible to create energy by turning a permanent magnet on and off, regardless of the method used, such as coils or moving shields.

Areas of Agreement / Disagreement

Participants express differing views on the feasibility of reducing the attraction between a steel plate and a magnet through induced electrical currents. There is no consensus on whether this method would lead to permanent changes in the magnetism of the steel plate, and some participants challenge the idea of generating energy from permanent magnets.

Contextual Notes

The discussion includes assumptions about the behavior of magnetic materials and the effects of electrical currents on magnetism, which may depend on specific conditions and definitions not fully explored in the conversation.

gloo
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I want to move a steel object/plate away from a magnet - Here is my questions:

1. Can I induce an electrical current to a steel plate just large enough to allow me to pull the plate away without much attraction to a magnet? So I guess it would kind of being like the reverse of turning on an electromagnet?

2. If this can be done...will it result in some kind of permanent reduction of magnetism for the steel plate if done repeatedly?
 
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I'm not certain what you are trying to do. Have you looked at magnetic chucks? They are devices that use variable air gaps to reduce the clamping between the chuck and the part being held.

For 1) the answer is yes. Just coil windings about the magnet and drive a current sufficient to null or reduce the field.
For 2) I think this depends on the B-H hysteresis curve of the magnetic material and how far along this curve the induced field goes.
 
Paul Colby said:
I'm not certain what you are trying to do. Have you looked at magnetic chucks? They are devices that use variable air gaps to reduce the clamping between the chuck and the part being held.

For 1) the answer is yes. Just coil windings about the magnet and drive a current sufficient to null or reduce the field.
For 2) I think this depends on the B-H hysteresis curve of the magnetic material and how far along this curve the induced field goes.

I am just trying to imagine a way for magnets to do work on an object -- hoping to maybe patent something but I am not very well versed on the deep workings of how magnets work.

-- in response to your answer # 1 -- I don't want to neutralize the magnet but the steel plate that is attracted to --- I am assuming yes?

-- in response to # 2 -- does the B-H hysteresis factor a function of how large the electric current is that is used to reduce the magnetism of the plate?
 
gloo said:
I am just trying to imagine a way for magnets to do work on an object

Magnets do work on objects through a number of ways. There is the ##dW=F\cdot ds## mechanical work. Then there is the energy term ##\int{B\cdot H dx^3}## which is the energy stored in the magnetic field. Typically ##H(B)## is a multi-valued function so as ##B## is changed work is done heating the object in proportion to the area enclosed in the ##B##-##H## curve. If you are trying to get help on something you feel is proprietary best of luck. I likely can't help.
 
What exactly are you trying to do? You can't make energy by somehow turning a permanent magnet on and off. It doesn't mater if you try to use coil or some sort of moving shield to turn off the magnet.
 

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