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Re: [Z_Scale] MRC 2800 Tech II Question re: Z Useage

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  • zbendtrack@aol.com
    ... No, and yes. At full throttle, this version of the 2800 would burn out the motors in seconds. So the answer is no. However, if you mechanically blocked
    Message 1 of 13 , Jan 1, 2006
      Michael:

      > Looking at one with the following specs:
      >
      > Output: Cab 1 14.0 VDC, 14.8 VAC Cab 2 14.0 VDC Then it says Total
      > Output: Cab 1 8.5VA Cab 2 8.5VA
      >
      > Is this the one that can be used with Z Scale?
      >

      No, and yes.

      At full throttle, this version of the 2800 would burn out the motors in
      seconds. So the answer is no.

      However, if you mechanically blocked the throttles such that the output could
      not exceed 10vdc, then the answer is a qualified yes.

      The "qualification" is that it would be fairly difficult to determine where
      10vdc is on the throttle knob. The non-sinusoidal output of the 2800 is great
      for slow speed operation, but it fools the vast majority of affordable
      voltmeters into giving false readings. And, you would have to make the measurement
      under "loaded" conditions (meaning a #93 automotive light bulb across the
      output).

      Simpler solution: The 2800 was manufactured in two formats: 10.1vdc and
      14.5vdc outputs (why in the &*@# do manufacturers do that?). Both packs carry
      the "model 2800" label and look identical (except for the printed labels). Find
      the 10.1vdc version instead of the 14.5 volt version. The 10.1vdc version
      was used to power up the layout at the National Train Show this last summer and
      everything put on the track ran well and safely. Including multiple loco
      consists.

      Hope this helps,
      Bill K.
      Houston


      [Non-text portions of this message have been removed]
    • John Cubbin
      I ve just put a couple of shots of the 10.6 VDC version of the MRC 2800 in the Photos section in a folder titled, cleverly enough: 2800_MRC:
      Message 2 of 13 , Jan 1, 2006
        I've just put a couple of shots of the 10.6 VDC version of the MRC 2800
        in the Photos section in a folder titled, cleverly enough: 2800_MRC:

        http://ph.groups.yahoo.com/group/z_scale/photos/browse/d8be

        John
        http://www.ztrains.com
      • zbendtrack@aol.com
        ... Great photos. And now I learned something new. There are three formats, not two, of the 2800. (10.1) (10.6) and (14.5) vdc output. And they are all
        Message 3 of 13 , Jan 1, 2006
          John:

          > I've just put a couple of shots of the 10.6 VDC version of the MRC 2800
          > in the Photos section in a folder titled, cleverly enough: 2800_MRC:
          >
          Great photos. And now I learned something new.

          There are three formats, not two, of the 2800. (10.1) (10.6) and (14.5) vdc
          output. And they are all labeled "2800." There out to be a law against that.

          Both 10.x volt outputs are in the "safe" output range, I'd say.

          Something else I thought about on the 14.5 volt version. The non-sinusodial
          output of the 14.5vdc version would burn out onboard solid state
          embellishments instantly, like the Richmond Control lighting modules, even if you were to
          hold the RMS value of the output down to 10vdc.

          So I'll change my answer to an absolute NO for the 14.5vdc version. Its not
          polite to burn out something in a "guest" loco on your layout. Or one of your
          own locos that has 3rd party solid state stuff onboard. That could include
          DCC-equipped locos being run on DC.

          Happy New Year,
          Bill K.
          Houston


          [Non-text portions of this message have been removed]
        • miked_r
          Thank you Michael, John & Bill! They should give them different model numbers, if not different version numbers at least!! Bill good point on RMS values-often
          Message 4 of 13 , Jan 1, 2006
            Thank you Michael, John & Bill!

            They should give them different model numbers, if not different
            version numbers at least!! Bill good point on RMS values-often not
            factored in or understood in electrical discussions.

            HAPPY NEW YEAR & HAPPY 1st ANNIVESARY TRI-STATE Z-SCALERS!!

            Michael (R. not H.) :-)

            --- In z_scale@yahoogroups.com, zbendtrack@a... wrote:
            <snip>
            > So I'll change my answer to an absolute NO for the 14.5vdc
            version. Its not
            > polite to burn out something in a "guest" loco on your layout. Or
            one of your
            > own locos that has 3rd party solid state stuff onboard. That could
            include
            > DCC-equipped locos being run on DC.
            <snip>
          • Joe Krepps
            All, So how does one order the right 2800? Joe
            Message 5 of 13 , Jan 1, 2006
              All,

              So how does one order the right 2800?

              Joe
            • Brad Saunders
              I ve been told that the only 2800 that is produced today is the higher voltage unit ... the 10.xV units are the original version of the power pack. Sometimes
              Message 6 of 13 , Jan 1, 2006
                I've been told that the only 2800 that is produced today is the higher
                voltage unit ... the 10.xV units are the original version of the power pack.
                Sometimes you find the older 2800s listed on eBay (and maybe other auction
                sites) ... this might be your only chance to find one unless some hobby
                shops still have stock of the older unit.

                Brad

                _____

                From: z_scale@yahoogroups.com [mailto:z_scale@yahoogroups.com] On Behalf Of
                Joe Krepps
                Sent: Sunday, January 01, 2006 12:58 PM
                To: z_scale@yahoogroups.com
                Subject: [Z_Scale] Re: Re: MRC 2800 Tech II 10 VDC Version Photos


                All,

                So how does one order the right 2800?

                Joe


                -Z- WARNING! HANDLE WITH CARE! Highly addictive in Small DoseZ!





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                [Non-text portions of this message have been removed]
              • zbendtrack@aol.com
                ... Could be, can t say. But if that s the case, there is absolutely nothing that wears out on the 2800 s, so auctions would be a reasonably safe route to
                Message 7 of 13 , Jan 1, 2006
                  Brad:

                  > I've been told that the only 2800 that is produced today is the higher
                  > voltage unit ... the 10.xV units are the original version of the power pack.
                  > Sometimes you find the older 2800s listed on eBay

                  Could be, can't say. But if that's the case, there is absolutely nothing
                  that wears out on the 2800's, so auctions would be a reasonably safe route to
                  follow. Prices range around the middle 20 dollar range. There's one on eBay
                  tonight in the original box for 9 dollars (at the minute).

                  Don't just search Z scale, search ALL scales since they might be listed under
                  HO through Z.

                  Hope this helps,
                  Bill K.
                  Houston


                  [Non-text portions of this message have been removed]
                • zbendtrack@aol.com
                  ... Some folks just don t like the word previous owned. I can appreciate that. If new is a requirement, please keep in mind that MicroTrains markets a
                  Message 8 of 13 , Jan 1, 2006
                    Another thought:

                    > >I've been told that the only 2800 that is produced today is the higher
                    > >voltage unit ...

                    Some folks just don't like the word "previous owned." I can appreciate that.


                    If "new" is a requirement, please keep in mind that MicroTrains markets a
                    single MRC throttle (MRC 1300) already modified for Marklin/MTL 10v maximums
                    brand new in a box. Sole anywhere MTL products are sold, and at a huge number of
                    places on the Internet. Its a very affordable unit.

                    Hope this helps, too.
                    Bill K.
                    Houston



                    [Non-text portions of this message have been removed]
                  • Glen Chenier
                    ... All good answers, as long as you keep the speed prototypical, feel the loco for excess heat, and know for sure that no Indy 500 operators will ever touch
                    Message 9 of 13 , Jan 2, 2006
                      --- In z_scale@yahoogroups.com, "miked_r" <miked_r@y...> wrote:
                      >
                      > Looking at one with the following specs:
                      >
                      > Output: Cab 1 14.0 VDC, 14.8 VAC Cab 2 14.0 VDC Then it says Total
                      > Output: Cab 1 8.5VA Cab 2 8.5VA
                      >
                      > Is this the one that can be used with Z Scale?

                      All good answers, as long as you keep the speed prototypical, feel the
                      loco for excess heat, and know for sure that no 'Indy 500' operators
                      will ever touch the throttle knob, this pack is fine, but different
                      from the other MRC power packs i've looked at.

                      I have a MRC 2800 Tech II 14.0 volt version permanently mounted in a
                      small N scale layout. Earlier today put an oscilloscope to it for the
                      first time to get some knob positions vs voltage for this thread, have
                      only looked at MRC 1370, MRC1400, and MRC1440 before.

                      Big surprise. The 14.0 volt 2800 is nothing like the others.
                      John_Ztrains, I took the liberty of adding these waveform photos
                      temporarily to your 2800_MRC album to show the difference. These
                      photos will be deleted in a few days. All waveforms are shown at 2
                      volts per vertical division on the screen.

                      The 1370 puts out 120 somewhat sine shaped pulses per second, shown in
                      blue. All pulses are the same amplitude and vary from zero up to over
                      20 volts at their peak depending on the throttle knob position. At
                      the voltage shown a MTL F7 was doing about 55 scale MPH.

                      The 1440 and the 1400 shown in yellow put out 60 sine pulses per
                      second separated by gaps at low throttle, at intermediate throttle the
                      pulse voltage increase and the gaps between large pulses gets filled
                      in with lower voltage pulses, at full throttle there are 120 pulses
                      per second all the same maximum voltage of over 20 volts and dropping
                      back to zero volts between pulses. Again the voltages shown are for a
                      MTL F7 at 55 scale MPH. I believe the MRC 1300 has the same output as
                      the 1400 according to Bill's observations from long ago.

                      The 2800 Tech II outputs 3-step ramped trapezoid shaped pulses
                      superimposed on a variable DC level. The photo shows 4 positions of
                      the throttle with 0 volts at 1 division up from the bottom on which
                      the lower white trace is sitting. This trace is with the knob at
                      about 20 on the dial. The second trace up is with the knob at about
                      30. The third up (yellow) is with the knob at 55, and the top blue is
                      with the knob at 75. Two small N scale locos were running from these,
                      but with the loco on or off made very little difference to the waveform.

                      The scope calculates Mean, RMS, and Maximum (peak) values. Using
                      these for the following table may help MRC 2800 Tech II 14.0 volt
                      users figure the maximum safe spot on the throttle knob setting. The
                      RMS is the important reading as this directly influences the heat
                      produced; the Mean is what a standard voltmeter would display. This
                      type of waveform that is superimposed on a DC level is more benign to
                      a Z scale locomotive than the sinusoid type pulses that return to zero
                      between pulses, and a typical meter will read closer to true value
                      since much of this voltage is DC.

                      Note this is only for the MRC 2800 Tech II rated at 14.0 volts. The
                      maximum knob position for Z scale should be 60 to 70, both cabs on
                      mine tracked farly close together in position vs voltage. Earlier 10
                      volt models may be very different, and might even be the sinusoid
                      pulse variety. If someone with a 10 volt model and a scope can have a
                      look it would be interesting to know.

                      Knob Mean RMS Max
                      0 0
                      10 0
                      20 0.93 1.29 2.48
                      30 2.73 3.08 5.04
                      40 4.45 4.74 7.28
                      50 5.85 6.08 8.64
                      60 7.61 7.77 10.2
                      70 9.03 9.15 11.6
                      80 10.9 11.1 12.6
                      90 13.6 13.7 13.8
                      100 14.1 14.1 14.1 pure DC
                    • zbendtrack@aol.com
                      ... That IS a surprise (the waveform). I m tempted to buy one just to tear into it and discover the circuitry that generates that interesting waveform.
                      Message 10 of 13 , Jan 2, 2006
                        Glen:

                        > Big surprise. The 14.0 volt 2800 is nothing like the others.

                        That IS a surprise (the waveform). I'm tempted to buy one just to tear into
                        it and discover the circuitry that generates that interesting waveform.

                        However, my concern is not limited to just motors anymore. Motors can handle
                        almost any waveform and peak voltages up to their limit of heat dissipation.
                        After all, they are just a simple coil of wire and a magnet, when you get
                        right down to it.

                        But solid state electronics is not so tolerant of peak voltages some
                        waveforms might present. With many folks adding electronic packages to the locos
                        (DCC, constant lighting, electronic flywheels, etc.) the peak value has become
                        more of a concern.

                        This is a special concern to module groups, or to owners of equipment who
                        might run on a module setup. In these situations, the owner of an embellished
                        loco may not be aware of what the module power pack is under the drapes, or its
                        output characteristics. As I mentioned in an earlier post today, its just not
                        polite to blow up a guest loco (or you own embellished loco) on your modules
                        (or home layout) due to a power pack/electronics mismatch.

                        We've recently had a thread on this group about blown up constant lighting
                        modules. And on another Z list, thread(s) about exploding capacitors. These
                        devices have sensitivities to peak voltages, not just the effective RMS value.

                        The absolute limit of 16vdc peak (11.3v sinusoidal RMS) for one lighting
                        manufacturer can be found here:
                        http://www.richmondcontrols.com/compati.html

                        I particularly noted the reference in your measurements to 20 volts (snips
                        below):

                        > The 1370 puts out 120 somewhat sine shaped pulses per second, shown in
                        > blue. All pulses are the same amplitude and vary from zero up to over
                        > 20 volts at their peak depending on the throttle knob position.

                        > The 1440 and the 1400 shown in yellow put out 60 sine pulses...<snip> all
                        the same maximum voltage of over 20 volts and dropping

                        > Note this is only for the MRC 2800 Tech II rated at 14.0 volts. The
                        > maximum knob position for Z scale should be 60 to 70, both cabs on


                        Perhaps those of us with suitable equipment should form a separate,
                        temporary, Yahoo group and set up a goal to locate and test as many "safe" power packs
                        we can? Then publish the list for those who are not technical?

                        I'm game.
                        Bill K.
                        Houston



                        [Non-text portions of this message have been removed]
                      • Glen Chenier
                        ... tear into ... Before taking the readings I thought the 2800 was just two 1400 s in the same box and never bothered looking closely until now. (2
                        Message 11 of 13 , Jan 2, 2006
                          --- In z_scale@yahoogroups.com, zbendtrack@a... wrote:

                          > That IS a surprise (the waveform). I'm tempted to buy one just to
                          tear into
                          > it and discover the circuitry that generates that interesting waveform.
                          <snip>


                          Before taking the readings I thought the 2800 was just two 1400's in
                          the same box and never bothered looking closely until now. (2 times
                          1400 = 2800) Silly of me... I should never assime things.


                          <snip>
                          > But solid state electronics is not so tolerant of peak voltages some
                          > waveforms might present. With many folks adding electronic packages
                          to the locos
                          > (DCC, constant lighting, electronic flywheels, etc.) the peak value
                          has become
                          > more of a concern.
                          > The absolute limit of 16vdc peak (11.3v sinusoidal RMS) for one
                          lighting
                          > manufacturer can be found here:
                          > http://www.richmondcontrols.com/compati.html
                          > I particularly noted the reference in your measurements to 20 volts
                          (snips
                          > below):
                          > > The 1370 puts out 120 somewhat sine shaped pulses per second, shown in
                          > > blue. All pulses are the same amplitude and vary from zero up to over
                          > > 20 volts at their peak depending on the throttle knob position.
                          >
                          > > The 1440 and the 1400 shown in yellow put out 60 sine
                          pulses...<snip> all
                          > the same maximum voltage of over 20 volts and dropping

                          Yes, the 1300,1370, 1400, 1440 can be hazardous to the add-ons if even
                          momentarily advanced too high from a slip of the hand. Semiconductor
                          junctions can fail instantly from overvoltage. A mechanical stop on
                          the knob is really a good idea if these extras are in the locomotive.
                          The 14.0 volt 2800 (the one that I tested) never went above 14.1V
                          even at full throttle so would seem to be a better design than the
                          others for safety of add-ons. But as MRC is now known to change
                          electrical specs without changing model numbers (this was news to me -
                          very interesting news...) caution is the word.

                          > Perhaps those of us with suitable equipment should form a separate,
                          > temporary, Yahoo group and set up a goal to locate and test as many
                          "safe" power packs
                          > we can? Then publish the list for those who are not technical?
                          >
                          > I'm game.
                          > Bill K.
                          > Houston


                          So am I. New group formed:

                          http://groups.yahoo.com/group/Z_Scale_Electronics

                          Let's see what we can learn about commercial power packs. I know only
                          the MRC packs that I own. All are welcome to join and learn /
                          contribute to power pack technish.

                          Wouldn't it be nice if power pack (and other railroad electrical
                          device) manufacturers actually printed the real technical
                          specification information in their literature? Just like the
                          manufacturers of stereo equipment?
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