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Re: Locomotive current demands

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  • Ole.Rosted@xxxxxxx.xxxxxxxxxxxxxx)
    ... [snip] ... Me! But I m not at all sure, that my question is relevant in the context. - What about the inner resistance of the ammeter? Is it a specific
    Message 1 of 13 , Jan 1, 2000
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      On Fri, 31 Dec 1999 22:52:42 EST, you wrote:

      >From: BJKRONEN@...
      >

      Bill and group:

      >Jeffrey and Bim:
      >
      >>Jeffrey: I suppose I'm not quite clear on what we're checking here though.

      [snip]

      >Who's next at the keyboard on this topic?

      Me! But I'm not at all sure, that my question is relevant in the
      context.

      - What about the inner resistance of the ammeter?

      Is it a specific relationship between inner resistance of loco and
      ammeter that will produce produce the readings mentioned? And does the
      loco resistance vary with rotational speed - so that you will get
      varying milli-amp readings depending on the point where wheel-spin
      sets in (wheels and tracks not beeing 100% clean and friction/weight
      relationship)?

      I guess everyone will see immediately, that I do not know a lot about
      these things! But....?

      BTW: the lights on my locos only turns on at a voltage where the
      current consumption makes the loco rather hot?? (Marklin locos)

      regards Ole Rosted, Denmark
    • Ed Scullin
      To Bill B and the list. I don t remember seeing anything on whether or not the track should be level, and would it be possible to use wheel slip at a specific
      Message 2 of 13 , Jan 1, 2000
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        To Bill B and the list.
        I don't remember seeing anything on whether or not the track should be
        level, and would it be possible to use wheel slip at a specific angle?
        I have my test track with a hinge on one end and a jack screw on the
        other so I can see how a loco will do on a grade.
        Have you or anybody tried using the "cheap" digital multimeters from
        Radio Shack etc as the source of current reading?
        Is there any place (database) that we could put our data into, and all
        get at? Somebody that has a web site to act as a server, but I don't
        know about having external data input to a database on the net. Don't
        want to burden the web site owner with having to manually input
        everybodys inputs.
        Ed Scullin
      • BJKRONEN@xxx.xxx
        ... We just kept it simple. Flat and level for the wheel slip current test. I d suggest computing grades may be more than some folks want to get involved
        Message 3 of 13 , Jan 1, 2000
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          Ed:

          > I don't remember seeing anything on whether or not the track should be
          > level, and would it be possible to use wheel slip at a specific angle?

          We just kept it simple. Flat and level for the wheel slip current test. I'd
          suggest computing grades may be more than some folks want to get involved
          with.

          > Have you or anybody tried using the "cheap" digital multimeters from
          > Radio Shack , etc., as the source of current reading?

          Yup, and its a problem. Digital meters sample the current a few times a
          second and display the results. More you pay, more samples per second.
          Problem is, there are a lot of variables and the digital meters tend to not
          have a consistent reading, rather the numbers on the meter just bounce around
          like you were playing roulette.

          But good old analog meters tend not to do that, and the needle stabilizes on
          a fixed point on the scale, so you can read it.

          > Is there any place (database) that we could put our data into, and all
          > get at?

          What about the archives of the OneList itself? There are a number of folders
          already there.

          *** Jeffrey MacHan: How does that work, list owner? ****

          Regards,
          Bill Kronenberger
          Houston
        • John L. Battey
          Sorry if dredging up ancient history offends anyone ... ... though. ... pulse power) ... performance and ... late. A goal to which I aspire most vigorously!
          Message 4 of 13 , May 13, 2006
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            Sorry if dredging up ancient history offends anyone ...

            --- In z_scale@yahoogroups.com, Dec 31, 1999, 9:52 pm,
            BJKRONEN@... wrote:
            >
            > Jeffrey and Bim:
            >
            > >Jeffrey: I suppose I'm not quite clear on what we're checking here
            though.
            >
            > There are two nightmares you can have with any model train in any scale:
            >
            > 1. Burn out the motor (with too high a voltage, or some types of
            pulse power)
            >
            > 2. Have a dysfunctional mechanism that gives you frustrating
            performance and
            > overloads the motor until it burns out, or tears up the gears.
            >
            > The question at hand addresses the detection of # 2 before it is too
            late.

            A goal to which I aspire most vigorously!


            > > Bim: What do you use to measure current???
            >
            > Most folks know that a volt meter measures electrical pressure
            expressed in
            > volts. In order to make that measurement one puts the meter in
            PARALLEL with
            > the power pack, the rails or the loco.
            >
            > In order to measure current, one has to put a meter in SERIES with
            the power
            > pack. Since the polarity of the power back can be reversed, a "zero
            center"
            > meter is appropriate. That means a meter that at rest, will have
            its pointer
            > in the middle of the scale, and not off to the left side like most
            meters. A
            > meter with 1amp-zero-1amp offers a usable reading, but can survive a
            dead
            > short across the rails. Remember, any current (including a short)
            will pass
            > through the meter on the way to the rails in a series connection.
            >
            > Likewise, a "zero center" voltmeter is quite appropriate too.
            Again, because
            > the power pack can reverse the polarity to the rails.
            >
            > If interest develops, any one of several of us on the list can put
            together a
            > list of parts from common (cheap) resources that folks can buy and
            use, with
            > little or no electrical knowledge. A number of how-to books already
            have
            > this information.
            >
            > But let's see if anyone agrees with the "normal" readings and the "test
            > procedure" before we advance to that step.
            >
            > Who's next at the keyboard on this topic?
            >
            > Bill Kronenberger
            > Houston

            What I would like to do is set up dual meters (Volts & Amps) for each
            of my power packs, or integrate the meters into a Z Bend Track control
            connecter. Where would I get the information as to parts & assembly
            for this project?

            John L. Battey in Roanoke, TX
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