Re: Magnetic force

On Fri, 20 Sep 2024 12:26:44 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:

On 9/20/2024 9:38 AM, Joe Gwinn wrote:

On Fri, 20 Sep 2024 00:11:05 -0700, Don Y
<blockedofcourse@foo.invalid> wrote:
 

I have an optically-couple "supervisory port" on my
devices.  A design requirement is that the outer surfaces
of the devices must be "wipe clean" -- no ridges or
grooves.
>
I mechanically attach the mating "cable" to the port
magnetically (an idea I stole from designing electric
power meters -- but, they aren't "wipe clean"!)
>
As I can't rely on any significant mechanical structures
to help maintain the attachment's position, that must
be guaranteed solely by the strength of the magnetic
bond.

 
This approach will attract and hold magnetic debris, like rust and
iron filings.  Is that a problem, or is wiping enough?  If the magnets
are strong enough, debris removal may be difficult to do in practice.

>
Are you expecting the non-magnet surface to assume a
magnetic state, over time?

Not if the non-magnet side is soft enough magnetically.

The actual magnet will be on the cable end so the
"wipe clean" surface will not inherently be magnetized.
And, the cable end should be easier to manipulate, "scrub",
etc (even REPLACE) as it is "portable".

That'll work so long as the magnet isn't too strong.

A good way to clean stuff off a magnet pole is adhesive tape.

I'd take a rare earth magnet and roll it around on the floor of the
garage, and see what you catch.

Joe Gwinn