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Re: [z_scale] Electromagnets and microtrains magne-matic couplers

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  • Stuart Firth
    It does strike me that there is a reasonable alternative that I have not as yet seen discussed in this particular forum . That is the use of relatively small
    Message 1 of 3 , Oct 8, 2002
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      It does strike me that there is a reasonable alternative that I have not
      as yet seen discussed in this particular 'forum'.

      That is the use of relatively small permanent magnets (for the purposes
      of un-coupling) physically manipulated to be where they are needed, and
      when.

      What I mean is to attach said magnets to a lever system that moves them
      up into an active position when they are needed to perform their
      intended task, and then drop away when un-needed.

      This has a number of positive virtues:

      a) Cheap

      b) Wiring can be avoided and 'activation' can be mechanical through the
      use of levers, pulleys and cables (in most instances).

      c) Avoidance of the imparting of 'stray' magnetic influences where they
      are definitely unwelcome.


      Electromagnets exhibit a magnetic radiation property that is far from
      'limited' to the intended area of efficacy ie. their 'mutual inductance'
      is annular.

      What this means is that a substantial area around their 'zone of
      operation' is exposed to large doses of magnetism in a form resembling a
      donut ('doughnut' for the English speakers out there). This magnetism,
      naturally enough, is then also magnetically charging everything metal in
      it's proximity........axles, wheels etc.

      From my reading of all matters related to 'Z hygiene', it seems that the
      greatest evil in our chosen hobby is anything that contaminates, or
      attracts contaminants to our trains, particularly metal ones.

      Further to this, it seems reasonable to suspect that large and
      ubiquitous doses of magnetism are not going to do wonders for the
      performance of motors.

      While my opinions and observations are not grounded in comprehensive
      expertise, I do indeed know what I am talking about and trust that I
      have provided food for some collective thought.

      Warm Regards to all,

      Stuart


      On Sunday, October 6, 2002, at 11:44 AM, zbendtrack@... wrote:

      > Daniel:
      >
      >> The Magne-Matic couplers are great. But one question ...
      >> Some of you are telling about electromagnets.
      >> What for an electromagnet you are using?
      >
      > You got really good advice regarding not to use permanent magnets on any
      > mainline. The couplers are simply designed to uncouple anytime the
      > couplers
      > go "slack" in the presence of a magnetic field. It doesn't matter if
      > the
      > train is creeping (intended uncoupling) or moving fast (unexpected
      > uncoupling).
      >
      > There are several "model railroad" electromagnets on the marketplace
      > (search
      > www.walthers.com) but they appear to have two real challenges when you
      > try to
      > use them:
      >
      > 1. They get extremely hot in seconds, and can even burn up
      > 2. They draw a tremendous amount of current (amps), to the point you
      > may
      > wish to have a second power pack just for the electromagnets.
      >
      > Both these problems are related to an insufficient iron core with very
      > few
      > turns of big wire around the core, which makes it cheap to manufacture
      > (in
      > some cases, in someone's garage).
      >
      > Now, I don't sell electromagnets and I don't get any
      > commissions/considerations from those folks who do. I pay the same
      > price as
      > anyone else. But I like things that work, and don't give me grief.
      >
      > I discovered a fellow modeler a few years ago, who had lucked upon a
      > large
      > lot of unused, surplus commercial grade electromagnets originally
      > intended
      > for the mainframe computer marketplace. They are just outstanding and
      > have
      > none of the above problems and work well in Z (and other) scales. I've
      > posted this source before, and you can find those posts in the archives
      > at
      > least twice since the list started.
      >
      > Here's the details to save your searching:
      >
      > Grade: Commercial, can be powered up for extended periods of time
      > without getting hot (or even very warm)
      > Coil: 81 ohms, approx. 150ma at 12vdc, 225ma at 25vdc.
      > Mounting: Directly under the ties/sleepers of Z scale track with
      > adhesive
      > Pictures:
      > http://members.aol.com/zbendtrack//em_side.jpg
      > http://members.aol.com/zbendtrack//em_face.jpg
      > http://members.aol.com/zbendtrack//em_depth.jpg
      > Source: Ralph Hall, PO Box 220, Horse Shoe, NC 28742
      > Email: starshine@...
      > Price: $20 for 4 (sold only in sets of 4)
      > Shipping: Don't know the current price for 4, but 8 magnets is $7.80
      > by
      > Priority Mail
      > Weight: About 4 ounces per magnet
      > Data: Comes with a drawing on how to use the accessory power
      > terminals
      > on a power pack, a common diode and capacitor, to
      > develop a steady voltage to run them through an
      > electrical
      > pushbutton.
      >
      > I will comment that the voltage you need to use with these
      > electromagnets is
      > predictably tied to how much maintenance you put into your MT
      > couplers. Like
      > anything mechanical, if you never clean and lubricate them, it will take
      > extra force to overcome friction/dirt to make things work well (about 25
      > vdc). If you periodically clean the MT coupler pockets and use the MT
      > dry
      > lubricant (as per MT instructions) then 12vdc will work well.
      >
      > Hope this helps
      > Bill K.
      > Houston
      >
      >
      >
      > [Non-text portions of this message have been removed]
      >
      >
      >
      > "Z" WARNING! HANDLE WITH CARE! Highly addictive in Small
      > DoseZ!
      >
      >
      > Your use of Yahoo! Groups is subject to
      > http://docs.yahoo.com/info/terms/
      >
      >
    • jmac_han
      Sounds like a great idea, Stuart. Here s another possibility that might be mechanically easier to build. Instead of a lever up into position, how about a
      Message 2 of 3 , Oct 8, 2002
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        Sounds like a great idea, Stuart. Here's another possibility that
        might be mechanically easier to build. Instead of a lever up into
        position, how about a simple push-pull rod with the magnet on
        the end of it. The magnet can be slid along simple guides into
        position.

        The 'off' position could be either in or out but I would suggest
        pulling the rod so that the magnet is in the "on" position. Most of
        us would prefer to have rods and levers pushed as close to the
        layout board as possible to avoid snagging them.

        Cheers,
        Jeffrey

        --- In z_scale@y..., Stuart Firth <sfirth1@p...> wrote:
        > It does strike me that there is a reasonable alternative that I
        have not
        > as yet seen discussed in this particular 'forum'.
        >
        > That is the use of relatively small permanent magnets (for the
        purposes
        > of un-coupling) physically manipulated to be where they are
        needed, and
        > when.
        >
        > What I mean is to attach said magnets to a lever system that
        moves them
        > up into an active position when they are needed to perform
        their
        > intended task, and then drop away when un-needed.
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