magnetizer

[spuffock]

I find myself with the intriguing problem of building a device to magnetize small magnets, with the restriction of using only the junk box, namely no thousand pound thyristors or cast unobtainium insulators.
The only thing I have in plentiful supply is ignorance, and 4 capacitors of 40 uf 5kv working.
I had thought that I would need to switch the capacitor(s) into the coil, and crowbar before the coil current falls to zero. I am looking at 5 kilovolts at a kiloamp or two.
Any ideas about how to build triggered spark gaps? Would a photoflash trigger transformer be good as a trigger? Any good ideas about avoiding blowing up a PIC every shot ?
That'll do for now.

 

[DerStrom8]

That seems awfully high-powered and deadly to just magnetize something. That could easily kill you, and cause fires, explosions, etc. I suggest you just use a car battery or something.
What do you plan on magnetizing, exactly?
Der Strom

 

[crutschow]

Yes, you just need high current, not voltage to magnetize items. A large battery, such as a car battery, can provide the current. Use enough turns of small wire to limit the current to a reasonable level. You only need to power the coil momentarily so you don't have to worry about heating from the high current.

As a kid I once re-magnetized some horseshoe magnets by wrapping a number of turns of wire around the poles and momentarily connecting the wire to the car battery. Re-magnetized them nicely.

 

[spuffock]

I want to magnetise some assemblies with neodymium magnets. The magnets cannot be supplied in the magnetised state, because the field of the magnets outside their assemblies could be dangerous. Also,assembling a live magnet will almost certainly cost a finger or two.
The magnetising coil will need a lot of amp turns, and if I have a lot of turns I have a lot of inductance, which means that with a low voltage it will take a long time to build up the amps I need. In this time the coil will melt. So I need a lot of volts to get the current up FAST, then dump the energy before the coil current reverses.
Unless anyone knows better?

 

[Gobbledok]

We also used to have a de-magnetizer. It was just an iron nail wrapped with a small coil and AC current running through it. Excellent for those magnetized side-cutters which the legs stick to every time you cut them off

In fact it was the magnetizer as well. Just use DC instead.

Edit: This was great for magnetizing screw-drivers but I doubt it would be any good for neodymium.

 

[shortbus=]

Don't know if this will help or not, its a two part article on making a "magnet charger"

part one; **broken link removed**

part two; **broken link removed**