Efficiency of Bar Type Magnet Re-Chargers

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Efficiency of Bar Type Magnet Re-Chargers

Post by BE_ZERO_BE » Sun Sep 22, 2019 2:34 pm

Bar type magnet chargers can do the job of re-magnetizing a flywheel magnet.
The efficiency of these type of magnet chargers can be improved by completing the magnetic circuit with a better magnetic conductor.
Magnetic flux flows in a similar manor to electricity.
It flows through conductors and is affected by conductor resistance.
In the sketch below the magnetic flux flows from the bar magnetizer into the flywheel magnet then out of the flywheel magnet through air back to the bar magnetizer.
Thus, making a complete magnetic circuit.
Steel is a good conductor of magnetic flux.
Air is a poor conductor of magnetic flux.
Materials have a property called permeability.
It is a measure of its ability to conduct magnetic flux.
Air has a permeability of about 1.0.
Carbon steel has a permeability of about 100.0 – i.e. a 100 times better conductor of magnetism.
Air is like a big resistor to magnetic flux.
Below is a magnet recharger I made by re-shaping a flywheel magnet and winding a coil on it.
It makes a complete magnetic circuit through steel.

Respectfully Submitted,

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Steve Jelf
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Re: Efficiency of Bar Type Magnet Re-Chargers

Post by Steve Jelf » Sun Sep 22, 2019 3:23 pm

I like to take that a step further by having the bar recessed inside the coil a few inches so the magnet is both touching the bar and also has the coil around it.

IMG_2851 copy.JPG
I don't know if this is superior to other arrangements, but it charges the magnets enough to hold 4 to 4½ pounds.
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Re: Efficiency of Bar Type Magnet Re-Chargers

Post by It's Bill » Sun Sep 22, 2019 3:33 pm

Steve, what do you use for a power supply, and do you "flash" it when charging, or make a continuous connection? Also, how do you tell what the polarity is of your charger?

Thanks, Bill

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