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Electromagnetic chuck - weak surface, strong on ends

leeko

Stainless
Joined
Jun 30, 2012
Location
Chicago, USA
Hi all

I have a new-to-me tiny "magnemite" electromagnetic chuck. The controller turns on and hums quietly, but the chuck doesn't seem to be working correctly. The flat surface of the chuck doesn't generate much holding power, while the ends of the plate (pictured) actually hold very well. This seems opposite to what it should be. Any suggestions on how to troubleshoot this?

Thanks!

Lee
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Sent from my SM-N960U using Tapatalk
 
Hi,
Bumping this thread to see if anyone has any suggestions.

I replaced all the wiring, which was very crusty. No change.

With a multimeter, the power supply is putting out ~8v DC when the label says 6v. From my limited understanding of electromagnets, more voltage would mean more holding power I think...

Hopefully someone here knows about electromagnets :) should this go in the recycle?

Thanks

Lee

Sent from my SM-N960U using Tapatalk
 
Hi,
Bumping this thread to see if anyone has any suggestions.

I replaced all the wiring, which was very crusty. No change.

With a multimeter, the power supply is putting out ~8v DC when the label says 6v. From my limited understanding of electromagnets, more voltage would mean more holding power I think...

Hopefully someone here knows about electromagnets :) should this go in the recycle?

Thanks

Lee

Sent from my SM-N960U using Tapatalk

Are you certain there is not ALSO an "AC component" riding on the Dee Cee off the back of a partial failure in the PSU?

If so, it could be trying to PARTIALLY de-mag, each pulse.

Which fits the symptoms. Electromagnetic chucks not being dependent on permanent magnetism in their materials.

Doubt you have a 6V battery or similar highly-filtered source with which to test at "pure" DC?

I do. I would.
 
Are you certain there is not ALSO an "AC component" riding on the Dee Cee off the back of a partial failure in the PSU?

The AC ripple from full-wave rectifying AC to DC is unlikely to matter.


Or, is it designed to hold 'across' the pads you picture as 'top' and 'bottom', i.e. N&S poles? That would require a minimum part size, but. . .

That's my reading too. I cannot really tell from the photo, but is the top face solid, or striped (brass-iron-brass-iron...)? If solid, then yes that face will be weaker that the two-pole face.

A clear photo of the plate below the on-off switch would be helpful.
 
WTF does that have to do with anything?

Which part of "partial failure" did you miss?

None. Low probability, and the OP said that the pull between the two big iron poles was strong while on the top pole alone it was weak. There is one coil, so all poles would be weak if a bad rectifier bridge were the issue.
 
Check the voltage on magnet winding. It must be near DC, if there is AC component then cheap multimeter can show something but its not correct. Usually power supply will fail as the winding in magnet is very simple and robust.

And if this is correct and you have access to winding and if the winding is made of segments, check the resistance of each segment AND check also the inductance - resistance deviation could be small when there are shorted windings but inductance will show it nice and clear.
 
None. Low probability, and the OP said that the pull between the two big iron poles was strong while on the top pole alone it was weak. There is one coil, so all poles would be weak if a bad rectifier bridge were the issue.

And yet he has the problem. "Probability" notwithstanding.

Takes near-zero time to check and ascertain whether or not the PSU is doing what it is meant to do.

It is far from new. Wiring isn't new, either.

Why - when there is a "problem" - would one just "trust it" and NOT check that it has a clean output as well as the correct one?

IS there but one coil? Or an array of several?

And if more than one, is there a fault in their distribution of the power.. or a leakage path bypassing one or more?

Is the power OK when not connected, but dragged-down when it IS connected?

"etc"

Not rocket insemination. Basic fault isolation.
 
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I know you're just perpetually a dickhead, but sometimes man, i really wish you'd give it a rest. Why are you so hell bent on being such a god damned ass hole?

Because he has been exposed by senior members of this forum as a pure bullshitter and fraud, this clown has never done anything here but trash others threads, and others personally.
Finally, the tide is turning however, and more are catching on to this troll and his addiction to posting 24\7 on this forum his useless nonsense.
I, and others have called him out as a 2 bit troll on a machinist forum that he is, but the addiction is too strong, he cant walk away, like a bug in a jar, that I have just shaken!

After his BS post he used to sign out "Bill with a simile icon" now its the blue demon icon, more fitting I think.
 








 
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