Fixed DC

Discussion in 'FAQs' started by DeaconF, Mar 31, 2004.

  1. DeaconF

    DeaconF Member

    Can anyone tell me what I use the fixed DC output from my TechII power suply for? Can I use it to power Peco PL10 motors? I have an issue with regards to moving 2 turnouts on one toggle switch. Somtimes it works sometimes it dosn't .
    Thanks Frank
  2. shamus

    shamus Registered Member

    The short answer is "NO" you need 16volt to power Peco PL10 point motors, just putting in 12volt DC, is not good enough.

    Also needed is some sort of passing contact switch or use a stud and probe (As I do) with a CDU (Capacitor Discharge Unit)

    The fixed 12v outlet can be used to power lights.
  3. Vic

    Vic Active Member

    Hi Deacon, Most any solenoid type switch machine works better on AC then on DC if you are not using a CDU as mentioned by Shamus. The reason is that the cycle of the AC current sorta gives more of a jolt to the solenoid coils. The drawback is that they will buzz when you activate them.

    Since you are trying to throw 2 turnouts at once you have to consider that your current draw is doubled. It may be that the size wire you are using for the machines is not large enough to handle the current required. Try using a larger gauge wire(s) to the machines. You can just double the existing wiring if you want to and it will accomplish the same thing.

    Also keep in mind that its always better to have some kind of a seperate power supply for lights, turnouts and accesories. Power packs have a common transformer to each output so the more "juice" you use for accessories is less "juice" that you have for operating the trains.

    Hope this helped.
  4. ezdays

    ezdays Out AZ way


    You are right. Every power pack that I've seen so far gives an overall rating, like 35 watts, but never the individual output ratings. The common transformer output winding is the reason.
  5. Vic

    Vic Active Member

  6. ezdays

    ezdays Out AZ way

    When I first got into the hobby, a bit over a year ago, I bought both HO and N sets to see which scale I would like better. I checked out the measly power packs that came with these sets and what horrified with what they were calling "DC" output. Half-wave rectification and no filter capacitor. I found a Tech 4 on sale and I was so impressed with its features and plused DC out that I bought a second one. I don't know if they run trains any better, but I felt more at ease using them.

    The past few months I have bought two layouts and as a result, I now own another Tech 4, about nine older model MRC's (including an "N scale" dual cab control) and a few more of those measly ones that came with sets. I noticed that on the older MRC's you can select a "pulsed" DC output. I haven't put these on a scope yet, but I am interesed to find out how clean the steady DC looks, and how they had achieved the plused output before there were any low cost microprocessors around.

    I know this probably doesn't add anything to this thread, but it does give you an insight as my opinion.:) :) I am really surprised how well these motors stand up to the garbage DC that some of these power packs put out. But, given a choice, I would always go for the ones with cleaner DC., and the current Tech 4's with pulsed output can't be matched by anything else right now.

    Boy, if this was one of "those" forums, this thread would ignite one of those DC vs DCC flaming wars.:rolleyes: :rolleyes: Not here though.:cool: :cool:
  7. DeaconF

    DeaconF Member

    You guys are fantastic. I thought it may have something to do with the wire. I will start running a larger one. thanks a lot for all your help.
    BTW this forum should lobby all model train manufacturers to include this site with every sale made. If I had known about The Gauge when I started, my layout would have been a lot better.
    thanks again Frank
  8. jon-monon

    jon-monon Active Member


    I believe the old MRCs are using full wave recitifed DC in normal mode and half wave in pulse. It works well with older loco's and the pulse does provide better low end power and creep. Some say your motor will heat up after a while if you pulse it too long. I've not had this happen. Sometimes they growl. If they growl and you leave them growling long, I'm sure they get warm.

    The problem with running newer loco's is not the pulse method or the noise, it's the use of resistance to control DC levels, which depends on currnet, and the newer ones don't deraw enough current. You can put an automotive light bulb across the output and run newer loco's.

    I don't think the noise will hurt the motors, but you could always add a big cap, and get "momentum" along with the quiet DC :D The old power packs might even smooth out once you are connected to the track and running a loco, as you have a PI filter (capacitance of the track and inductance of hte motor) :D :D :D Procede with caution.
  9. Fred_M

    Fred_M Guest

    Another thing about two selonide machines on one switch is sometimes one selonide has lower resistance and robs the power from the higher resistance one. I've seen this a lot on CD units. The fix is more power and bigger wires or two switches. I'm slowly converting my layout back to "the choke cable" throws in the facia. When my double cross had 4 selonides on it I ran them off a 24V 1+amp AC power pack. Now it's on cables (rods). I prefer the retro method. :) FRED
  10. 60103

    60103 Pooh Bah

    I use a couple of trainset power packs to run my turntables -- I hooked a handheld unit to the AC terminals. I also use it to power my Tortoise switch machines through a bridge rectifier.
    I would ignore the fixed DC terminals unless you dedicate the pack to lighting or other accessory uses.
    Watch out for switch machines running together. Different brands/models are a bad idea. Even the same model may have different characteristics in different years.
  11. Lightbender

    Lightbender Member

    Hello Frank,

    There is one useful thing you can do with that extra 12 volts that hasn't been mentioned. A light bulb that lights up the controller area and both makes it easier to see and lets you know that it's switched on. Of course only an idiot with half a brain would start ripping out wiring and test equipment to find out why the trains aren't running and not notice the power switch on the controller was turned off. The power bar light was on...hrumphh.

    Hello Fred, I have a pair of Pecos and decide to throw them with cables, nice positive springy action I thought would make it easy. Instead of going out and buying a bike brake cable or choke cable I looked around.....Oh oh. I found a set of old strings from my electric bass and some fish tank plastic tubing. I had to lengthen one of them, so I soldered a short section of coat hang wire to the string. It worked well so I buried it in the subroadbed...woops. Yup, about a year later the solder joint gave way and I couldn't get the wire out so now that set of points has been electrified. I still have the other one manual. I'd prefer manual throws but my turnouts are on many levels and distances. My turnouts are all powered with an independent CDU like Shamus suggests.
  12. Fred_M

    Fred_M Guest

    I drill a hole under the center of the throw tie and come up from underneith with the wire. That way the cables are accessable. FRED
  13. Lightbender

    Lightbender Member

    Thanks Fred, That would have been handy advice a few years back...haha.
  14. Fred_M

    Fred_M Guest

    I retrofit on plywood/cork, Go two ties each way and drill down with a 1/16. Go under and connect the holes and drill up carefully with a 3/8 bit in center. You have some buffer with the cork. Dig cork out with knife. FRED

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