Atlas N Scale Motor Discovery

Hardcoaler Mar 10, 2019

  1. Hardcoaler

    Hardcoaler TrainBoard Member

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    I have a few old Atlas SD-35s that were in need of repair and I'd hoped to do it inexpensively, but discovered something about Atlas motors that has added to the complexity.

    I knew that Atlas had the original Fast Speed motors (identified by the typical black plastic case around the motor) and a Slow Speed motor introduced perhaps 10 to 15 years ago (identified by gray plastic case around the motor). What I didn't know was that Atlas has introduced an even slower Scale Speed motor which runs super slow. Unfortunately it has the same black plastic look as the Fast Speed motor. :oops:

    So, Atlas has three types of motors, each with a different speed.

    I've found a visual cue that might help distinguish between the old Fast Speed motor and the newest Scale Speed motor. As noted, both have a similar black plastic case surrounding the motors, but parts within the Fast Speed motor's rotating assembly have a graphite-colored look and the Scale Speed motor parts within the rotating assembly have a greenish tint. At least this is the case with the motors sitting before me.

    Perhaps this will help you to identify what you need if you are seeking to speed match another locomotive in your collection. This is of major importance to us DC operators and the speed differences between the three types are significant enough to perhaps be important to DCC owners too.
     
    Last edited: Mar 10, 2019
  2. DCESharkman

    DCESharkman TrainBoard Member

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    DCC requires less worry about the varied speeds of the motors with the use of TRIM. I have Kato locomotives running with Atlas locomotives in DCC consists with both Atlas "Scale SPeed" and non Scale Speed.
     
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  3. Doug Gosha

    Doug Gosha TrainBoard Member

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    Thanks for the information, Dan.

    So in DCC (I don't use it) the maximum speed of any consist has to be that of the slowest loco, then.

    Doug
     
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  4. Jim Reising

    Jim Reising TrainBoard Member

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    Which is why there are no Atlas locos (except the Oakville switcher, pair of GP38s) running on the Sub.

    I had a couple of FVMs that slow but replaced the motors...

    Even though DCC is wonderful at speed matching, Doug is correct. You can slow a loco down but you can't make it run faster that the motor will allow.
     
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  5. DCESharkman

    DCESharkman TrainBoard Member

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    This is why I said it was less worry and not "no worry". I have found many of the the Atlas Scale Speed motors to not really be scale speed. They are more limited to a top speed of 100 SMPH. Since I speed match at lower speeds of operation, I have very few locomotives that will present problems. I see trim values of 40 on Kato locomotives and comparable values of trim at 86 on the scale speed motors for a top speed of 70 SMPH.

    I do have some locomotives that for some reason or another do not scale speed as well, and they become single operators on branch lines or industry tracks.

    And another variant is the decoder that is used as well. Some decoder just do better with some motors than others. I have pulled NCE decoders from Atlas and replaced the decoder with a Zimo decoder and the locomotive ran completely differently. This was on several EMD SD60M's that were factory DCC. I believe this is because the Zimo decoder adjusts itself to the motor in a similar manner that the ESU decoders do.

    To my knowledge, not other decoders do this. So this may also a be another way to get better performance with a slow motor.
     

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