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Magnet drag in the environment

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  • Magnet drag in the environment

    Hi,

    I wanted to make a couple of obsevations about metal surrounding the monopole. I mentioned before that a compass will deflect slightly at least a foot away from a ceramic magnet. That's with a single magnet, so it may be even greater with a monopole rotor. People might want to check their own rotors to see how far the fields go. So any steel within range of the rotor will decrease your cop, if only slightly.

    So I'm sitting here looking at my mp sitting on the floor, and the magnets at the bottom are about 6" off the floor. What's under my monopole are wood floor with finishing nails in them, so that means there are steel nails 6" from my magnets. Oops. Obviously I better a base under the machine to get it away from the nails, and it better be a solid stand as any wobble in the machine just means more losses in the system.

    At one point I had it positioned near a wall to make some space, and I started thinking about the drywall screws/nails in the wall, just a couple of inches away from the magnets. Oops again. Even worse would be next to an electrical outlet, because not only the plug will have steel in it, but if the plug is in a steel box that's really gotta hurt.

    Some years back I was waving a compass around a concrete floor and the needle was deflecting all over the place as it passed what must have been rebar in the floor. The rebar had magnet fields of it's own, plus it's a big chunk of steel, so you really don't want your monopole sitting on a concrete slab.

    Plus I've been using small steel toggle switches on my boards and they are too close. Even the alligator clips on the battery are too close. I'm trying to keep the wires as short as reasonably possible and that puts the clips too close. I googled on stainless alligator clips and copper ones, so they are readily available. Time to change that out.

    Something to note about stainless steel is that there are different grades and some have more steel in them. A magnet will stick or drag on some of the cheaper grades, so don't just assume that if it's stainless that it won't drag. Check it before you use it.

    I want an on/off switch to shut the machine off but don't want the steel in the toggle so need to find something nonmagnetic. They have knife switches that go on the battery so maybe I can find a copper one to put on the primary. I like having a switch because if I need to shut it off in a hurry I don't disconnect the charging battery by mistake.

    Happy c.o.p.ing!

    Robert

  • #2
    Hi,

    I was at the hardware so I picked up some stainless screws to show what I was talking about. I'll save a thousand words and post a pic:

    Click image for larger version

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    They have all the little bags of stainless screws hanging in different sizes, so I took a ceramic magnet and waved it by some of the bags. Some bags would pull over to the magnet and stick and others wouldn't do anything. So there is a wide variation in the composition of metals in these fasteners, even though they are all the same brand. The stainless washers pretty much all stuck to the magnet.

    When it came time to buy, rather than worrying about checking every screw, I just went over to the brass screw section.

    Robert

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