165 Crane...Can it be de-magnetized?

An AC demagnetizer should work just fine to demagnetize the steel parts of the head.  It may be a good precaution to disconnect at least one of the wires from the cranes' electromagnet assembly before using the demagnetizer to prevent a high electromagnetically induced voltage from back feeding into the crane circuitry.

Whenever demagnetizing an object, best practice is to first power the demagnetizer at arms length from the object to de-mag, bring the de-magger in towards the subject item slowly, move it slightly side to side a few times near the object without touching. Continue this side to side motion while slowly increasing the distance between the demagnetizer and the object until they are at arms length again before powering off the demagnetizer.

Using a demagnetizer does run the risk of introducing a high voltage spike as the magnets steel core is surrounded with a coil of wire. It might be better to disassemble the magnetic and just demagnetize the core. The screw eye in top of the magnetic used to lift it is also the screw that holds it all together. Remove the ring and put a pin through the eye to unscrew it. There are a lot of pieces in the magnetic so keep track of them.  This is also the same process used when the wires require replacement.   This is the same problem they have is a real junk yard. Sometimes they will slide the magnetic across the edge of the gondola to knock everything off the magnetic.

To be absolutely certain that it is the magnet is at fault (which it sounds like you have done) can you verify that with all the power disconnected, the magnet still attracts steel items? 

@Arthur P. Bloom posted:

To be absolutely certain that it is the magnet is at fault (which it sounds like you have done) can you verify that with all the power disconnected, the magnet still attracts steel items?

Art, I'll try it again.  The one thing I didn't do was disconnect the accessory from the transformer...even though the transformer was turned off.  I assumed the accessory controller magnet switch was sufficient in the 'off' position to totally eliminate extraneous voltage.  But, hey...I'm not the expert.  I've learned enough about the damage static charges can do to things just by touching them.

Later.

KD

I have one of these at the workbench, when I want something demagnetized, it happens!

@Arthur P. Bloom posted:

To be absolutely certain that it is the magnet is at fault (which it sounds like you have done) can you verify that with all the power disconnected, the magnet still attracts steel items?

Art...

Had a chance to retest the crane magnet this evening.

Powered the 165 with 12v AC.  The magnet grabbed a 7/8" steel washer.  Turned the controller switch off.  The magnet still retained the washer.  Disconnected the power from the accessory.  The magnet still held the washer.

I waited 10 minutes to see whether there would be any decay in the attraction.  Zip, nada, none.

However!....

When I then manually withdrew the washer from the un-powered magnet, and tried to replace the washer to the magnet, there was insufficient attraction to hold the washer.

Ditto smaller, lighter weight washers.

And, no, there's not any sticky, gummy gook on the face of the magnet confusing the analysis.  Hey, I took a scrap piece of tissue paper and tried to have it stick to the un-energized magnet face to test that idea.

Very strange.  Very interesting.  But still a bit frustrating to the operation I'd hoped for.

So after trying to get any iron/steel object from the workbench to attach to the unpowered magnet coil, I've decided that a de-mag tool would be pointless.  In its current unpowered state it has no attraction ability whatsoever.

I need a physicist and a glass of wine...maybe not in that order.

Ok, who remembers the discussion in electromagnetic fields class on hysteresis and residual magnetism? Isn't this what is  happening and is based on the properties of the material Lionel used in the magnet? We may be barking up a tree here?

The loads I have that always drop are wood barrels with a large tack on top and the plastic cement container with a washer glued on top. these appear to balance non magnetic weight (wood and plastic) and the metal part to give the desired result.

@dkdkrd posted:

So after trying to get any iron/steel object from the workbench to attach to the unpowered magnet coil, I've decided that a de-mag tool would be pointless.  In its current unpowered state it has no attraction ability whatsoever.

I think you'd be amazed to find out that the demagnetizer would indeed probably work.  I've done several of these over the years that developed residual magnetism.  I didn't bother to try to explain in detail the phenomenon, I just hit them with the demagnetizer.

@gunrunnerjohn posted:

I think you'd be amazed to find out that the demagnetizer would indeed probably work.  I've done several of these over the years that developed residual magnetism.  I didn't bother to try to explain in detail the phenomenon, I just hit them with the demagnetizer.

GRJ...

O what the heck!  Your advice has been golden platinum through the years.  My little Micro-Mark demag is hardly the degausser extrordinaire that yours is, but it's done a reasonable job in knocking the attraction from tweezers, screwdrivers, steel mini-nuts&bolts, etc., etc..  So, zap we will.  I'll post results FWTW.

Thanks for the encouragement, all.

KD

Update 1:05PM O1FE22:

Nope.  Gave it multiple shots with the de-magnetizer.  Hasn't changed a thing.  Maybe I can find someone locally who has a mongo demagger...like GRJ has...with more 'oomph'. 

Or, it's time to rethink the accessory's future...