Forums General Problem Solving
  • Topic: Brakes?

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    • December 27, 2018 11:51 AM EST
      • Tiburon, California
         
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      Brakes?

      For the gravity car I am envisioning, I'll want brakes.  This is an unpowered car that runs, like a roller coaster, down a mountain.  I have not seen any remotely operated (or any) brakes for model trains. Do such exist?

    • December 27, 2018 3:00 PM EST
      • Saint Helena, CALIFORNIA
         
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      I seem to remember an article in Model Railroader (about 50 years ago) on how to build an operating hump yard.  Since I was a young wipper-snapper back then I think they used soft bristle brushes mounted between the rails and solenoids to selectively apply friction to slow down or stop the cars.

       

      Perhaps a search for something like "model railroader operating hump yard" will yield the desired information.

    • December 27, 2018 3:30 PM EST
      • Vail, Az
         
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      With today's new magnets and some experimentation I bet you could slow 'em as if by magic! Use the repel feature, make track mag smaller so momentum carries the car past to the next one.

      Kind of like reverse Mag lev to MagDrag

      ____________________________________

      John

       

      The older I get, the less I know, please don't make me prove it.

       

       

    • December 27, 2018 6:47 PM EST
      • Pittsburgh, Pennsylvania
         
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      Or you could build a miniature version of an eddy current brake.

      ____________________________________

      Shannon car Shops
      Home of the infamous leg lamp

      I.A.R.R.R. Member #12

      and King Butt Modeler

    • December 28, 2018 12:09 AM EST
      • Elverta, CA
         
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      Michael

       

      Look at adapting an electromagnetic brake for RC aircraft. Specifically the small electric 'EDF' fan jets. Of coursce you'll need a RC system or similar ilk to operate.

       

      Michael

    • December 28, 2018 3:09 AM EST
      • Vail, Az
         
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      Centrifugal friction brake? Weights spin outward to drag on the rim. Rim is stationary and the axle with the weights, passes through.

      ____________________________________

      John

       

      The older I get, the less I know, please don't make me prove it.

       

       

    • December 28, 2018 7:05 AM EST
      • Saint Johns, Florida
         
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      3.5 years ago this topic was discussed and Kevin Strong came up with an idea. Unfortunately the photos he posted can no longer be gotten. His narrative is pretty good though.

      https://www.largescalecentral.com/forums/topic/24300/gimmie-a-brake?page=1

      This post was edited by Joe Zullo at December 28, 2018 7:07 AM EST
      ____________________________________

       

       

    • December 28, 2018 8:31 AM EST
      • Lancaster , Ohio
         
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      Use real dynamic braking, a small permanent magnet motor driven from an axle with a resistor across the motor terminals to provide a drag load, it would require some experimentation to find the best value of resistor to use.

    • December 28, 2018 1:58 PM EST
      • Fort Myers Beach & Annapolis, Florida & Maryland
         
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      Gary Buchanan, FOG said:

      Use real dynamic braking, a small permanent magnet motor driven from an axle with a resistor across the motor terminals to provide a drag load, it would require some experimentation to find the best value of resistor to use.

      In the slot car field you short the motor terminals after the power is removed, and the back-EMF has to work against the magnet, so it slows down more quickly.  Not sure you need a resistor, though a variable manual resistor might let you tune the amount of 'braking'.
      http://slotcarillustrated.com/portal/forums/showthread.php?t=33638

       

       

      This post was edited by Pete Thornton at December 28, 2018 1:58 PM EST
      ____________________________________

       

        Pete

    • December 28, 2018 2:03 PM EST
      • Fort Myers Beach & Annapolis, Florida & Maryland
         
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      John Caughey said:

      Centrifugal friction brake? Weights spin outward to drag on the rim. Rim is stationary and the axle with the weights, passes through.

      I like that idea.  Many engines have a "centrifugal governor" so finding one shouldn't be too difficult.  Then, as John says, make sure the outer rim rubs on some brake material so the governor can't go any faster.

       

       

      Microcosm makes them: just google "Microcosm P60 Mini Steam Engine Flyball Governor"

      This post was edited by Pete Thornton at December 28, 2018 2:06 PM EST
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        Pete

    • December 28, 2018 2:09 PM EST
      • Tiburon, California
         
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      Some great ideas.  The RC brakes used in other areas may be the thing, though a PM motor with a variable resistor or back emf might give much finer control.  A shoe against the wheel rim would be more prototypical, but probably very hard to modulate

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