Demagnetize

[rick9345]

Homebuilt demagnetize/magnetize from large 3 ph motor?
Anybody tried it? Sugestions.

 

[Hawkeye]

Bear in mind that, without the armature in place, the coil will draw a lot more current than the motor would. Also, if you connect it to 3-phase power, it will have a rotating magnetic field. It might have a tendency to make the tool you're demagnetizing try to spin in your hand. Haven't tried it, though.

 

[John Hasler]

You might try connecting all three windings in series across 120VAC.

 

[Tony Wells]

It's been done, I'm sure. I have read articles about it. Can't find any right quick this morning, but here is a guy who used a smaller motor. He makes the important point about DC used to magnetized and AC to DEmagnetize an object. In principle, this is what you need to do.

http://www.elteh.net/english-articles/magnetizer--demagnetizer.html

 

[jpfabricator]

When underground steel pipe becomes magnitized its near impossible to weld on during repairs or maintanance. The old welder I learned from would wrap the ground lead around the pipe and start welding.
If it needed tweeking sometimes we would make more wraps around the pipe. He never had a repair, or a bum weld via X ray inspection.
He told me there was certain ways (ie clockwise or counterclockwise) to wap the lead, depending on wich side of the Earths equator you were on. He said he had never worked in the southern hemisphere to find out though.


Sent from somewhere in East Texas Jake Parker

 

[rick9345]

A how to/illustration before I start poking around would be nice.

 

[Inflight]

Rick,
Sounds like a fun project, but do you really need a motor sized demagnetizer? I just use a radioshack video tape eraser I picked up for a buck at a local garage sale. Works well for things like screwdrivers and other handheld tools.

 

[rick9345]

some is good, more is better