Discussion in 'FAQs' started by yellowlynn, Oct 2, 2008.

  1. yellowlynn

    yellowlynn Member

    I have a question concerning a power pack for G gauge. I keep trains running at a pediatric clinic (2 seperate trains). The Xformers came with an Aristocraft starter set, so they are so-so, but work out OK. They have a slide switch for F-R-Off. Will an HO powerpak run G for a while so I can fix or replace it. These trains are not funded, so I can't just go buy one. Will HO heat up too much? Or will it run good for a time?

  2. 60103

    60103 Pooh Bah

    Lynn: the HO pack will be compatible with G; Lostock Junction (OO/HO) was running using a number of G gauge power packs (because of the radio control an the 5 amp supply).
    Can you find out what the power consumption of the trains is or, faiing that, what the output of the current packs is? (amps or watts) Then find an HO pack with at least that.
    I think the only place in the DC universe that's incompatible is Z scale and only because they use a 9V maximum (but I may be wrong).
  3. ezdays

    ezdays Out AZ way

    The most important aspect of your power pack is the rating. Like 50103 said, max amps out or power (watts or VA) output. I don't know the current draw on a G scale, I could measure the one I have, but it runs on an el-cheapo 11 VA power pack which means it takes less than 3/4 of an amp of current to run it. I've got an identical-looking one that is only 7 VA, enough for my N scale, but I wouldn't try to run the G scale with it. There should be a label or some markings on the unit to tell you its rating.
  4. yellowlynn

    yellowlynn Member

    I'll need to check on the ones I'm using. The one I plan on using is an MRC 1500, with o-20VDC and 12 ma. I'll have to wait until I go to town next to check on the "G" ones.

  5. ezdays

    ezdays Out AZ way

    Look at that again, you might mean, "12 VA". A 12 ma power pack is not even enough to light a light. That's 12 milliamps, or 12/1000 of an amp.
  6. yellowlynn

    yellowlynn Member

    OK, OK, you got me on that one. I knew there was an A in it, I just got the other letter wrong. It says 20VDC 20VA ??VAC TOTAL 22VDC 12VA. I hope I got that right. I can't remember it long enough to get back to the computer. Anyway, does that make it strong enough?

  7. Squidbait

    Squidbait Recovering ALCO-holic

    OK, so your 20VDC 20VA pack is going to produce 1A at 20 volts DC (VA = volts x amps). The other pack is only going to produce .5A at 22 volts.

    I don't know what the power requirements of your G scale trains are, but I'm betting the .5 A pack is pretty much at its limit. I'd think you'd want 1A or better.
  8. ezdays

    ezdays Out AZ way

    I'm not the G scale go-to guy, but I do have a G-scale loco and two cars that I ran last Christmas using the 11 VA pack. I'm not sure what the voltage setting was, but for under the tree you can be sure it was low. I think the grandkids ran it off the rails a few times though.:eek: :eek: I'm thinking you're right that a 12 VA pack is about the limit even without any accessories running.
  9. yellowlynn

    yellowlynn Member

    These trains run 8 hours a day, 5 1/2 days a week, so I believe I'll try for a little more power. It sounds like my MRC will do until I find one. They run about half throttle, so that may be a redeeming factor. Those little ones that came with starter sets have lasted a couple years, and one is still going strong. The forward-reverse switch on one is bad, it only works in one direction.

    Thanks all.
  10. ezdays

    ezdays Out AZ way

    You can always add an external reversing switch. All you need is a DPDT (double pole, double throw) switch. I'll show you how to wire it up if you want.

    Running trains for eight hours a day will generate a bit of heat in the transformer so it's always best to use a power pack that's over-rated for your needs.
  11. yellowlynn

    yellowlynn Member

    G power

    I went into town today and swapped out transformers. The one going bad is from an Aristocraft set. The output is 0-21 VDC, 15 VAC and the total output is 22VA max. That MRC of mine appeared a mite weak, but will do for a day or two.
    I took the back off this one and the F-R switch is solid connection to a circuit board, so there is no way to replace it, Since trains will run in the one direction OK, I think I'll just tell the nurse that tends it to never use that switch and it will be OK. A replacement is about $50.

    Thanks for the help, all. And Don, I don't think it is worth trying to wire up an external switch. Thanks for the offer.


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