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build your own magnet charger


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10/4/2005 2:15 PM
DoctorX
build your own magnet charger
check this article out....  
 
http://www.magnetoparts.com/inst_quide.htm  
 
there is an article here which tells you how to build your own magneto charger. With a little bit of rework, this should fit the bill nicely for building a very capable magnet charger. Now you can buy uncharged alnico pole pieces and magnetize them yourself.  
 
DoctorX
 
10/4/2005 4:57 PM
Spence

Maybe just a hint of overkill I think.  
Still, the magneto on my '65 Land Rover has sat on the shelf for many a long year waiting for restoration....
 
10/10/2005 10:31 AM
RedHouse
Coincidentally there was a show on the Discovery Channel last week all about magnets and how they changed our industrial operations (motors and machines etc) but what got my attention was that they showed some AlNiCo and Ceramic magnets getting charged for the first time after being manufactured.  
 
The raw-uncharged shaped magnets were clamped into a holding device about a dozen or so at a time, the device was inserted into a coil assembly and then the machine charged-up like a camera flash and gave the magnets a single large, fast, jolt.  
(just a fraction of a second, but lotsa current in the coil)  
 
Interestingly they called "Ceramic" magnets "Ferrite" magnets.
 
11/7/2005 11:54 AM
anonymous
The owner of the site that article's posted on, Bill Lopoulos, is a friend of mine. I was into old engines way before I got into guitars.  
 
That charger certainly is overkill in size terms for charging pickup magnets. It's designed for charging large horseshoe shaped magnets made of tungsten or hardened carbon steel used in old magnetos. The emphasis is on being able to saturate a large cross section of this relatively "soft" material. I'm not sure it would produce the needed flux density for fully charging AlNiCo magnets. Those chargers often do use large capacitors to discharge through the coils, producing a very high field strngth for a very short pulse, which is all that is needed.
 
11/7/2005 11:55 AM
John Culp

Sorry for the anonymous post. That was me.
 
11/7/2005 1:07 PM
DoctorX
This sort of gives me an idea....sort of.  
 
If you took a large photo flash unit and fed the output into a set of coils and holding fixture, could that be used as a magnet charger? Also, since the better photoflash units have adjustable outputs, could that feature be used to "dial in" the amount of energy you would use to magnetize AlNiCo? Custom magnetizations per pole, maybe?  
 
Please note I am not talking about the photoflash units that sit on top of a 35 mm camera. I am referring to the types the pros use for studio work. The great big heavy bastards used to fire off large Xenon flash tubes.  
 
Just another nightmarish idea.....  
 
Thanks,  
 
DoctorX
 
11/7/2005 5:39 PM
John Culp

Sounds like an idea. You'd have to analyze it for the current the flash unit would put out in the coil and the flux density produced.
 

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