Proto 2K ALCo S-1 stall current draw

Discussion in 'FAQs' started by Topo, Sep 24, 2002.

  1. Topo

    Topo Member

    Finally, I have measured the stall current draw of my Proto 2K ALCo S-1 switcher.
    I have measured it two times (with the loco running in different direction each time) and in two different locos, at notch-8 while having stopped the flywheels. The greatest value I have obtained is 0.38 Amp; so I think that this nice locomotive will be OK with an small N/Z size decoder rated at 0.5 Amp. :D

    I ask myself why the manufacturers don't include these and other values, as the bulb voltage/amperage rating, in the instructions sheet. :confused:
    Sure that they know the specifications of the motors they use, and it would not increase the manufacturing fees to advice "less than 0.5 Amp." or "between 0.5 Amp. and 1 Amp.", instead of the vague "Motor with low amperage drawing" noticed in the Life&Like Proto 2K sheets.

    Please, be warned that this is the value that I have obtained in MY locos. It can be supposed with a certain safety margin that all P2K S-1's share the same motors, but I have no way of be 100% sure about YOUR locomotive. :rolleyes: So don't take my advice like a bullet-proof warranty (and don't blame me about burned decoders if it happens that, under the influence of the Universe Mystic Powers, Life&Like have put a more glutton motor in your loky :eek: :rolleyes: :( ).
  2. Gary Pfeil

    Gary Pfeil Active Member

    Javier, I don't know if I missed a previous post asking for info on this unit, but I installed a digitrax DN121 in my S unit and it fit with no problem. I have never yet checked a stall current as I just make the assumption that all the fairly recent locos (say within 3 to 4 years) will draw no more than half amp. Even the smallest Digitrax decoders will handle 1 amp, so I use them and never give it another thought. Even my 20 year old brass gets 1/1.5 amp decoders with no problems so far.

  3. Topo

    Topo Member

    Hi, Gary

    I know that I could have installed one of the new tiny Digitrax DZ143 (or another 1Amp. decoder that fits under the S-1 hood), that can feed 1.25Amp., but I wanted to install a Lenz in these switchers.
    In other locos, I have tried both the Digitrax DH163 and the Lenz LE1024, and have found that, for switching, I like more the Lenz decoders, and for 'main line' running, the Digitrax are more appropiate. I realize that this is only my personal choice, and others can (sure that someone will do) disagree. :rolleyes:
    The LE1024 would fit into the S-1, but the smallest Lenz decoder with back-EMF is the LE0521 (that only can feed 0.5 Amp.). I was curious about if it could be used safely with the S-1, but I didn't find noticed anywhere the stall current drawing of this loco, thus it is that I did the checking.

    It would be nice to have an online database with these and other measures. It would do some things easier for the modelers to resource to it and have the values already taken instead of re-doing that things. So I only wanted to contribute the S-1 values. :D ;)
  4. Gary Pfeil

    Gary Pfeil Active Member

    Javier, Do you find the Lenz decoders provide better slow speed operation? If so, is that with or without setting speed tables? Frankly, I haven't used speed tables yet, but have been satisfied with performance without doing so. I'd be interested in knowing your thoughts.

  5. Topo

    Topo Member

    Gary, Well, in my limited experience, based only upon two decoders (Digitrax DH163LO and Lenz LE1024), the Lenz decoders provide a far slower speed than the Digitrax ones. I have checked they in a P2K GP7 and a P2K SW8 with similar results. Also, the Digitrax have some nice features (like the on-board rectifiers, that save you of tinkering with resistors) that I miss in the Lenz.

    I have found the Lenz very easy to configure for very low speeds without using speed tables. Only adjusting the starting voltage (CV2=1) and the repetition rate (CV9=2), I was able to make the locos run at a crawl. On the contrary, IMHO the Digitrax is a lot of trickier to adjust. I was never able to configure it to such slow running, in spite of tinker a lot with the three CV's that manage the back-EMF feature (CV's 55, 56 & 57), and with the "Switching Speed" (CV54). Usually, the loco was jerky, "jumping" around when running at slow speed. Finally, I gave up and set the CV's 55, 56 & 57 to "full back-EMF", like the "On/Off" in the Lenz one, and this cured some of the loco jerkiness at slow running (that was de facto, a lot faster than with the Lenz).

    I didn't intend to set up as an expert in the DCC stuff (in fact, I'm a newcomer to it), so it's very possible that somebody else can be able to configure the Digitrax better than me. Setting speed tables "at hand", CV by CV, is a very time-consuming task. I have seen announced in several DCC sites some decoder-programming devices that, plugged in the computer, can do the job a lot more easy, but I have none (...yet ;) ).

    It seems that this "decoder war" issue (Digitrax VS Lenz) generate a lot of heat in other forums. For me, the things are less passionate: the Digitrax is very fine in my GP7, at main line speed, and the Lenz crawls wonderful in my S-1 and SW8 switchers :D :D (now, if only Soundtraxx managed to build a sound unit the size of DZ143 or LE0521... with 'bean-size' speakers!!! :rolleyes: )
  6. Gary Pfeil

    Gary Pfeil Active Member

    Javier, Interesting, thanks for the info. I have not used either of the decoders you mention. The decoders I have are either Soundtrax or Digitrax (DH121, DH140, a couple DN140 and 121), also a couple NCE. The DN121 is in the S1 switcher and I felt the slow speed is good. It may just be that I'm happy with a higher minimum speed than others. That is, it is slow enough to switch realistically. I read reviews (even before DCC, just reviews on loco performance) that state it takes 10 seconds to go from tie to tie and I wonder why I would want to do that. I also have no decoders with back EMF, so can't form an opinion. It sounds like I ought to pick up a Lenz decoder one day just to check it out. Thanks again.


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