Loading ...
Sorry, an error occurred while loading the content.

Re: [z_scale] Z scale MRC Transformer modified by MTL

Expand Messages
  • zbendtrack@aol.com
    ... This list s archives contain frequent very positive experiences with the MRC 1300 in Z scale (search on 1300). It s unique sinusoidal waveform goes a long
    Message 1 of 27 , Nov 5, 2003
    • 0 Attachment
      Michel:

      > Does anybody has a comment on the MRC 1300 transformer sold by Micro-
      > Trains Lines (MTL)(item #195); MTL has externally modified it to
      > operate savely z scale. Is it a good alternative...

      This list's archives contain frequent very positive experiences with the MRC
      1300 in Z scale (search on 1300). It's unique sinusoidal waveform goes a long
      way toward making 3 pole motors into "creepers" (low speed operation).

      However, you need to make the same mechanical modification to it that
      MicroTrains does: block the throttle knob so that it cannot rotate past the 3:00
      position on a 12 hour clock face.

      MTL just adds a stickon plastic front panel that catches the pointer on the
      knob at 3:00. No electronic/electrical modifications are made to the pack by
      MTL.

      Hope this helps.

      Bill K.
      Houston


      [Non-text portions of this message have been removed]
    • ted_lamar@peoplesoft.com
      I think it is a great alternative... All they did was EXTERNALLY modify it with a small stop that disallows turning the throttle knob too far. Problem is,
      Message 2 of 27 , Nov 5, 2003
      • 0 Attachment
        I think it is a great alternative...

        All they did was EXTERNALLY modify it with a small "stop" that disallows
        turning the throttle knob too far.

        Problem is, you can get regular MRC 1300's for about 15 bux, and the MT
        ones I have seen are around 30+.....

        I use the regular ones and am careful not to over power my trains.
        Really, you shouldn't need to go that fast. If you have kids that run your
        Z, and they treat them like slot cars, then you should have the modified
        ones.

        I've also heard of people modifying them by themselves - or just putting a
        mark on the dial to remember what the top end is.

        T





        dufoca
        <dufault.michel@u To: z_scale@yahoogroups.com
        qam.ca> cc:
        Subject: [z_scale] Z scale MRC Transformer modified by MTL
        11/05/2003 05:59
        AM
        Please respond to
        z_scale







        Hi !

        Does anybody has a comment on the MRC 1300 transformer sold by Micro-
        Trains Lines (MTL)(item #195); MTL has externally modified it to
        operate savely z scale. Is it a good alternative...

        Many thanks,

        Michel Dufault
        Châteauguay (Québec, Canada)



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


        Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
      • Helmut Paule
        Hi Michel, I have 4 MRC 1300 , I was not satisfied with the mechanical stop to run my trains... I modified the Transformer windings to get max 9-10 Volts
        Message 3 of 27 , Nov 5, 2003
        • 0 Attachment
          Hi Michel,

          I have 4 MRC 1300 ,
          I was not satisfied with the mechanical stop to run my trains...
          I modified the Transformer windings to get max 9-10 Volts output.
          The low speed was improved and satisfactory for me.
          Any Electroniker could do the Job, takes not longer than 30 minutes.

          "Z" Greetings, Helmut

          ----- Original Message -----
          From: "dufoca" <dufault.michel@...>
          To: <z_scale@yahoogroups.com>
          Sent: Wednesday, November 05, 2003 8:59 AM
          Subject: [z_scale] Z scale MRC Transformer modified by MTL
        • Edward Scullin
          Helmut This sounds like a good article for Ztrack, or could you elightnen us on the list, or both. Ed Scullin ... SNIP __________________________________ Do
          Message 4 of 27 , Nov 5, 2003
          • 0 Attachment
            Helmut
            This sounds like a good article for Ztrack, or could you elightnen us
            on the list, or both.
            Ed Scullin

            --- Helmut Paule <hpaule@...> wrote:
            > Hi Michel,
            >
            > I have 4 MRC 1300 ,
            > I was not satisfied with the mechanical stop to run my trains...
            > I modified the Transformer windings to get max 9-10 Volts output.
            > The low speed was improved and satisfactory for me.
            > Any Electroniker could do the Job, takes not longer than 30
            > minutes.
            SNIP


            __________________________________
            Do you Yahoo!?
            Protect your identity with Yahoo! Mail AddressGuard
            http://antispam.yahoo.com/whatsnewfree
          • Glen Chenier
            ... with the MRC ... goes a long ... operation). ... Is the MRC 1370 similar to the 1300? MRC doesn t have a 1300 picture on their website, but presumably
            Message 5 of 27 , Nov 5, 2003
            • 0 Attachment
              --- In z_scale@yahoogroups.com, zbendtrack@a... wrote:
              >
              > This list's archives contain frequent very positive experiences
              with the MRC
              > 1300 in Z scale (search on 1300). It's unique sinusoidal waveform
              goes a long
              > way toward making 3 pole motors into "creepers" (low speed
              operation).
              >

              Is the MRC 1370 similar to the 1300? MRC doesn't have a 1300 picture
              on their website, but presumably they are similar.

              The 1370's output is full wave recified sine, or 120 pulses per
              second at 60 Hz input. All pulses are the same variable voltage as
              set by the throttle knob. Works good, but the 1400 series is better.

              The MRC Tech II's (MRC 1400 series) have a nicer feature - at low
              throttle, the output is mainly half wave rectified, 60 pulses per
              second with gaps between them (every second pulse is missing or
              reduced voltage). As the throttle is advanced the reduced-voltage
              pulses increase along with the main pulses to become 120 pulses per
              second at full throttle. This 2-step variable frequency makes for
              even smoother slow running, but the knob rotation must still be
              limited for Z scale. Or run them at prototypcal max speed only
              instead of racing; two 40 foot boxcar lengths per second is about 55
              SMPH. At correct scale speed motors will not overheat.

              The difference can be seen in the photos section, last entry in the
              second album page. Both scope waveforms have been set to drive a
              Micro-Trains F7 and two 40 foot boxcars at 55 smph. The blue at 8.56
              volts peak is the MRC1370, the yellow at 12.6 volts peak is the
              MRC1440. The Micro-Trains F7 runs much nicer on the yellow waveform,
              and when reduced to 5.5 volts peak the loco takes 60 seconds to move
              it's own length. It likes square rather than sine shaped pulses even
              better.
            • Edward Scullin
              A friend who is an electroniceer gave me a spec sheet for a LM117/LM317a/LM317 three terminal adjustable voltage regulator. It shows a 28Vdc input, but is
              Message 6 of 27 , Nov 5, 2003
              • 0 Attachment
                A friend who is an electroniceer gave me a spec sheet for a
                LM117/LM317a/LM317 three terminal adjustable voltage regulator. It
                shows a 28Vdc input, but is adjustable 1.2 to 37 volts. Not being an
                electonics guy, what would happen if we fed it up to 12 volts from a
                HO power pack, and had it adjusted (by resistor selection ) to give a
                max of 8 -10 volts?
                This is just a thought.
                Ed Scullin

                --- Glen Chenier <chenierfam@...> wrote:
                > --- In z_scale@yahoogroups.com, zbendtrack@a... wrote:
                > >
                > > This list's archives contain frequent very positive experiences
                > with the MRC
                > > 1300 in Z scale (search on 1300). It's unique sinusoidal
                > waveform
                > goes a long
                > > way toward making 3 pole motors into "creepers" (low speed
                > operation).
                SNIP
                > The difference can be seen in the photos section, last entry in the
                >
                > second album page. Both scope waveforms have been set to drive a
                > Micro-Trains F7 and two 40 foot boxcars at 55 smph. The blue at
                > 8.56
                > volts peak is the MRC1370, the yellow at 12.6 volts peak is the
                > MRC1440. The Micro-Trains F7 runs much nicer on the yellow
                > waveform,
                > and when reduced to 5.5 volts peak the loco takes 60 seconds to
                > move
                > it's own length. It likes square rather than sine shaped pulses
                > even
                > better.
                >
                >


                __________________________________
                Do you Yahoo!?
                Protect your identity with Yahoo! Mail AddressGuard
                http://antispam.yahoo.com/whatsnewfree
              • Glen Chenier
                ... an ... a ... Could be done, the LM317 itself would need a heat sink if it was asked to drop too much voltage and power too many locos at once, (heat
                Message 7 of 27 , Nov 5, 2003
                • 0 Attachment
                  --- In z_scale@yahoogroups.com, Edward Scullin <sculline@y...> wrote:
                  > A friend who is an electroniceer gave me a spec sheet for a
                  > LM117/LM317a/LM317 three terminal adjustable voltage regulator. It
                  > shows a 28Vdc input, but is adjustable 1.2 to 37 volts. Not being
                  an
                  > electonics guy, what would happen if we fed it up to 12 volts from a
                  > HO power pack, and had it adjusted (by resistor selection ) to give
                  a
                  > max of 8 -10 volts?
                  >

                  Could be done, the LM317 itself would need a heat sink if it was
                  asked to drop too much voltage and power too many locos at once,
                  (heat produced = voltage dropped times current through it). A no-
                  cost heat sink can be made by bolting the regulator to an old tin
                  can. If you can touch it without burning yourself it's big enough.

                  Another way to drop voltage is to cascade silicon diodes in series.
                  Each diode drops about 0.6 to 0.7 volts, depending slightly on the
                  current through it. Diodes from radio shack (1N4002 or similar) can
                  handle 1 amp, enough for Z scale locos. To drop 4 volts in the above
                  example 7 diodes would do it. Two diode strings paralleled in
                  opposite directions are needed for reverse voltage to reverse the
                  loco.

                  Problem is a lot of these HO power packs can hit 20-25 volts peak
                  when cranked wide open, that takes a lot of diodes. In this case, if
                  the goal is to protect your locos from certain kids (racing car
                  driver wannabees)the LM317 approach is better. But the loco
                  reversing needs to be installed after this regulator, or use two
                  regulators in opposite sides of the circuit with a bypass diode
                  across each one to handle reversing. Then only one regulator at a
                  time is actually put to use in it's correct direction polarity.

                  I really prefer Helmut Paule's idea. Start with a low maximum
                  voltage first. Never opened up an MRC pack, but if the transformer
                  secondary is centertapped re-wiring to half voltage would certainly
                  be the easiest solution. The hardest part would be fighting with
                  those special-tool recessed screws that MRC uses to discourage opeing
                  without breaking the housing.
                • Helmut Paule
                  ... From: Glen Chenier To: Sent: Wednesday, November 05, 2003 2:58 PM Subject: [z_scale] Re: Z scale MRC
                  Message 8 of 27 , Nov 5, 2003
                  • 0 Attachment
                    ----- Original Message -----
                    From: "Glen Chenier" <chenierfam@...>
                    To: <z_scale@yahoogroups.com>
                    Sent: Wednesday, November 05, 2003 2:58 PM
                    Subject: [z_scale] Re: Z scale MRC Transformer modified by MTL


                    >
                    > I really prefer Helmut Paule's idea. Start with a low maximum
                    > voltage first. Never opened up an MRC pack, but if the transformer
                    > secondary is centertapped re-wiring to half voltage would certainly
                    > be the easiest solution. The hardest part would be fighting with
                    > those special-tool recessed screws that MRC uses to discourage opeing
                    > without breaking the housing.
                    >

                    Hi Glen, Z_list

                    I promised to describe with pictures how I modified the MCR 1300.

                    About the screws, I modified a screwdriver to match the MCR screws
                    with a Dremel, but also needle files, or a fine teeth sawblade will do the job.
                    I have a picture of the change needed to open the housing without breaking it.

                    As I cant attach it to the mail, you must wait until I finish the write up OR
                    get me the your home address and I will forward.

                    Just to mentioned, If the Throttle is still under warranty , it is lost.
                    But if you can do the Modification you can fix any trouble popping up.

                    "Z" Greetings
                  • Glenn Patterson
                    I bought one of these several months ago and I am very pleased with it. It have more current capability than the Marklin transformer. I have only run it on an
                    Message 9 of 27 , Nov 5, 2003
                    • 0 Attachment
                      I bought one of these several months ago and I am very pleased with it. It have more current capability than the Marklin transformer. I have only run it on an oval test track that I have been using to break in my engines, but I have been able to get some very nice slow speed results after letting my engines run in. There are two markers on the transformer that you need to pay attention to on is for Marklin engines and the other is for Micro Trains. "Do not" run the either engine type over the set point or you will damage your engine.
                      I have had engines run for over an hour with no problems. Good luck, Glenn
                      ----- Original Message -----
                      From: dufoca
                      To: z_scale@yahoogroups.com
                      Sent: Wednesday, November 05, 2003 5:59 AM
                      Subject: [z_scale] Z scale MRC Transformer modified by MTL


                      Hi !

                      Does anybody has a comment on the MRC 1300 transformer sold by Micro-
                      Trains Lines (MTL)(item #195); MTL has externally modified it to
                      operate savely z scale. Is it a good alternative...

                      Many thanks,

                      Michel Dufault
                      Châteauguay (Québec, Canada)


                      Yahoo! Groups Sponsor
                      ADVERTISEMENT




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


                      Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


                      [Non-text portions of this message have been removed]
                    • Bill Powers
                      Hi All, Call MRC and buy their $8.00 resister pack made for this use. Goes between transformer and track. Bill ... From: Glenn Patterson To:
                      Message 10 of 27 , Nov 5, 2003
                      • 0 Attachment
                        Hi All, Call MRC and buy their $8.00 resister pack made for this use. Goes between transformer and track. Bill
                        ----- Original Message -----
                        From: Glenn Patterson
                        To: z_scale@yahoogroups.com
                        Sent: Wednesday, November 05, 2003 4:56 PM
                        Subject: Re: [z_scale] Z scale MRC Transformer modified by MTL


                        I bought one of these several months ago and I am very pleased with it. It have more current capability than the Marklin transformer. I have only run it on an oval test track that I have been using to break in my engines, but I have been able to get some very nice slow speed results after letting my engines run in. There are two markers on the transformer that you need to pay attention to on is for Marklin engines and the other is for Micro Trains. "Do not" run the either engine type over the set point or you will damage your engine.
                        I have had engines run for over an hour with no problems. Good luck, Glenn
                        ----- Original Message -----
                        From: dufoca
                        To: z_scale@yahoogroups.com
                        Sent: Wednesday, November 05, 2003 5:59 AM
                        Subject: [z_scale] Z scale MRC Transformer modified by MTL


                        Hi !

                        Does anybody has a comment on the MRC 1300 transformer sold by Micro-
                        Trains Lines (MTL)(item #195); MTL has externally modified it to
                        operate savely z scale. Is it a good alternative...

                        Many thanks,

                        Michel Dufault
                        Châteauguay (Québec, Canada)


                        Yahoo! Groups Sponsor
                        ADVERTISEMENT




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


                        Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


                        [Non-text portions of this message have been removed]


                        Yahoo! Groups Sponsor
                        ADVERTISEMENT




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


                        Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


                        [Non-text portions of this message have been removed]
                      • zbendtrack@aol.com
                        ... I ve not familiar with that MRC product. They may sell a resistor pack, but its a very unwise choice for track power, I would suggest. Since the voltage
                        Message 11 of 27 , Nov 5, 2003
                        • 0 Attachment
                          Bill:

                          > Hi All, Call MRC and buy their $8.00 resister pack made for this use. Goes
                          > between transformer and track. Bill

                          I've not familiar with that MRC product. They may sell a resistor pack, but
                          its a very unwise choice for track power, I would suggest.

                          Since the voltage drop across a resistor is proportional to the current drawn
                          through it (Ohms law) the voltage to the track would vary significantly with
                          the grade, number of cars pulled, tight turns versus straight track, different
                          loco's, etc.

                          Keeping anything near a steady speed of the train would require constant
                          adjustment on the throttle as it goes around the layout.

                          It's awful easy to just restrict the throttle knob rotation, and enjoy a near
                          constant speed with the excellent electronic regulation that's inside the
                          power pack.

                          Sorry for the difference in opinion.

                          Bill K.
                          Houston


                          [Non-text portions of this message have been removed]
                        • Bill Powers
                          Bill, This is fairly new and recommended by them. I don t know enough about electronickes to offer an opinion. : ) Bill ... From: zbendtrack@aol.com To:
                          Message 12 of 27 , Nov 5, 2003
                          • 0 Attachment
                            Bill, This is fairly new and recommended by them. I don't know enough about electronickes to offer an opinion. :>) Bill
                            ----- Original Message -----
                            From: zbendtrack@...
                            To: z_scale@yahoogroups.com
                            Sent: Wednesday, November 05, 2003 7:34 PM
                            Subject: Re: [z_scale] Z scale MRC Transformer modified by MTL


                            Bill:

                            > Hi All, Call MRC and buy their $8.00 resister pack made for this use. Goes
                            > between transformer and track. Bill

                            I've not familiar with that MRC product. They may sell a resistor pack, but
                            its a very unwise choice for track power, I would suggest.

                            Since the voltage drop across a resistor is proportional to the current drawn
                            through it (Ohms law) the voltage to the track would vary significantly with
                            the grade, number of cars pulled, tight turns versus straight track, different
                            loco's, etc.

                            Keeping anything near a steady speed of the train would require constant
                            adjustment on the throttle as it goes around the layout.

                            It's awful easy to just restrict the throttle knob rotation, and enjoy a near
                            constant speed with the excellent electronic regulation that's inside the
                            power pack.

                            Sorry for the difference in opinion.

                            Bill K.
                            Houston


                            [Non-text portions of this message have been removed]


                            Yahoo! Groups Sponsor
                            ADVERTISEMENT




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


                            Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


                            [Non-text portions of this message have been removed]
                          • Glen Chenier
                            ... use. Goes between transformer and track. Bill Any chance this is a constant voltage drop regulator rather than a resistor?
                            Message 13 of 27 , Nov 5, 2003
                            • 0 Attachment
                              --- In z_scale@yahoogroups.com, "Bill Powers" <wjpo@c...> wrote:
                              > Hi All, Call MRC and buy their $8.00 resister pack made for this
                              use. Goes between transformer and track. Bill

                              Any chance this is a constant voltage drop regulator rather than a
                              resistor?
                            • zbendtrack@aol.com
                              ... use. Goes between transformer and track. Bill Any chance this is a constant voltage drop regulator rather than a resistor? On the MRC website, they show a
                              Message 14 of 27 , Nov 5, 2003
                              • 0 Attachment
                                >Hi All, Call MRC and buy their $8.00 resister pack made for this
                                use. Goes between transformer and track. Bill

                                Any chance this is a constant voltage drop regulator rather than a
                                resistor?

                                On the MRC website, they show a "AT880" device under $10, described only as:

                                Quote the website:
                                Capable of lowering a power pack’s top voltage output by 4 volts.
                                If you’ve been having top voltage issues, here’s a solution. The Universal
                                Voltage Reducer lowers the top voltage output of the unit by approximately 4
                                volts. It works for any gauge and is especially useful with N Scale applications
                                where top speeds are too fast. Installs in series between the power source
                                and the track.
                                unquote:

                                Sure does sound like a mirrored string of diodes or a fixed regulators, given
                                the limited description. Either would give a constant voltage drop,
                                regardless of current load.

                                Unfortunately, it would also:

                                (1) make the first 20 to 30 degrees of throttle rotation "dead" - meaning no
                                output to the track until the pack reached 4 volts output, and

                                (2) worse, it would chop off the beginning and end of the sinusoidal
                                waveform, making it squared off, and thus negatively affecting low speed performance.

                                But, if the ad copy reads correct, and all you want to do is lower the top
                                speed, it would work fine for that.

                                Why turn the throttle up so high in the first place, I ask myself?

                                Oh well.
                                Bill K.
                                Houston





                                [Non-text portions of this message have been removed]
                              • M. Gottschalch
                                Hi Helmut, I hope you are still doing good health wise and also in everything else. I read your post with great interest so when you get done with the write up
                                Message 15 of 27 , Nov 6, 2003
                                • 0 Attachment
                                  Hi Helmut,

                                  I hope you are still doing good health wise and also in everything else.
                                  I read your post with great interest so when you get done with the write
                                  up could you please email me a copy.

                                  Thanks,
                                  --
                                  Manfred

                                  PS. I need to get to the next H&R train open house. It is always a lot
                                  of fun. Hope to see you there.
                                • Glen Chenier
                                  ... regulators, given ... drop, ... meaning no ... sinusoidal ... speed performance. ... the top ... 1. It would be nice to make a device with low drop at low
                                  Message 16 of 27 , Nov 6, 2003
                                  • 0 Attachment
                                    --- In z_scale@yahoogroups.com, zbendtrack@a... wrote:
                                    >
                                    > Sure does sound like a mirrored string of diodes or a fixed
                                    regulators, given
                                    > the limited description. Either would give a constant voltage
                                    drop,
                                    > regardless of current load.
                                    >
                                    > Unfortunately, it would also:
                                    >
                                    > (1) make the first 20 to 30 degrees of throttle rotation "dead" -
                                    meaning no
                                    > output to the track until the pack reached 4 volts output, and
                                    >
                                    > (2) worse, it would chop off the beginning and end of the
                                    sinusoidal
                                    > waveform, making it squared off, and thus negatively affecting low
                                    speed performance.
                                    >
                                    > But, if the ad copy reads correct, and all you want to do is lower
                                    the top
                                    > speed, it would work fine for that.
                                    >
                                    > Why turn the throttle up so high in the first place, I ask myself?


                                    1. It would be nice to make a device with low drop at low voltage
                                    input and max drop at max input. Can be done by sensing the
                                    instantaneous powerpack output and following with a variable
                                    regulator.

                                    2. Such a device would retain the sinusoidal pulse shape, although
                                    squaring up the pulse with a diode string is not such a bad thing.
                                    The gap time between pulses would increase. The motor would develop
                                    more low speed torque (what we want) at the expense of more heat
                                    (acceptable only up to a limit but controlled by reducing the
                                    voltage). If it would digitally divide by 2 for a lower frequncy
                                    even better. Lower frequency pulse at about 30 Hz works very well
                                    for the MT 5 pole motors (never tried Marklin, but will soon when
                                    that little starter set from Walthers arrives - back ordered). I'm
                                    guessing right now, but by watching MT locos with the shells off i
                                    can see the motor turn through the crack along the top of the
                                    chassis. I think the lower frequency pulse takes advantage of the
                                    natural motor cogging to fake a 'stepper' motor - ie the motor turns
                                    1 cog, or fifth revolution, for each pulse at the correct low voltage
                                    and time duration. The limit here is the headlamp flicker which gets
                                    annoying when the frequency is too low, incandescent bulbs such as
                                    used in the MT are more forgiving of low frequency than LED lamps.

                                    But for all this why make it an add-on to an overvoltage power pack?
                                    Start fresh with a proper speed controller.

                                    3. Yup. Why race?
                                  • Jeremy Brandon
                                    ... For more on cogging, see what I wrote back in October: http://groups.yahoo.com/group/z_scale/message/16864 ... The limit really depends on what your eyes
                                    Message 17 of 27 , Nov 6, 2003
                                    • 0 Attachment
                                      --- "Glen Chenier" <chenierfam@c...> wrote:
                                      > I think the lower frequency pulse takes advantage of the
                                      > natural motor cogging to fake a 'stepper' motor - ie the motor
                                      > turns 1 cog, or fifth revolution, for each pulse at the correct
                                      > low voltage and time duration.

                                      For more on cogging, see what I wrote back in October:

                                      http://groups.yahoo.com/group/z_scale/message/16864


                                      > The limit here is the headlamp flicker which gets
                                      > annoying when the frequency is too low.

                                      The limit really depends on what your eyes perceive as steady motion.
                                      Movies at 26 frames per second appear smooth, but below that
                                      frequency your brain processes fast enough to see the individual
                                      images. So I reckon a 40 millisecond pulse rate, or 25 pulses per
                                      second, is about the minimum to avoid the loco appearing to shake as
                                      it moves. If each pulse turns the motor one cog, that is the slowest
                                      the motor can turn.

                                      In practice, it is extremely difficult to drive a motor one cog at a
                                      time. If the pulse is too small, the motor turns less than one cog
                                      and flicks back to where it started - you can hear it buzzing but it
                                      doesn't move. If the pulse is too big, the motor turns more than one
                                      cog occasionally - you can see the jerks. (I have made a controller
                                      which automatically chooses the correct pulse size for turning one
                                      cog at a time, so I know it can be done.)

                                      Jeremy.
                                    • Glen Chenier
                                      ... as ... slowest ... Yes, 25 Hz for flicker also is about the minimum. ... it ... one ... You are right, perfect sync between pulse and motor cog is not
                                      Message 18 of 27 , Nov 6, 2003
                                      • 0 Attachment
                                        --- In z_scale@yahoogroups.com, "Jeremy Brandon"
                                        <Jeremy.Brandon@t...> wrote:
                                        > So I reckon a 40 millisecond pulse rate, or 25 pulses per
                                        > second, is about the minimum to avoid the loco appearing to shake
                                        as
                                        > it moves. If each pulse turns the motor one cog, that is the
                                        slowest
                                        > the motor can turn.

                                        Yes, 25 Hz for flicker also is about the minimum.

                                        > If the pulse is too small, the motor turns less than one cog
                                        > and flicks back to where it started - you can hear it buzzing but
                                        it
                                        > doesn't move. If the pulse is too big, the motor turns more than
                                        one
                                        > cog occasionally - you can see the jerks. (I have made a controller
                                        > which automatically chooses the correct pulse size for turning one
                                        > cog at a time, so I know it can be done.)

                                        You are right, perfect sync between pulse and motor cog is not
                                        achievable but it is possible to get close enough for all practical
                                        purposes as you have shown. With a loco that has a low gear ratio
                                        the individual cogs are not very perceptable as motion and the jerks
                                        are invisible. Don't know how Marklin drives are set up, but the MT
                                        has a gear reduction between the motor rotor and the main worm
                                        driveshafts which helps immensely, compared to my N scale locos that
                                        have the motor rotor direct coupled to the worm shaft without this
                                        extra reduction stage.

                                        Could some Marklin owners add to this and describe the gearing in
                                        their locos?
                                      • Helmut Paule
                                        Hi Bill, You are absolutely right ! you don t have to be sorry for your Opinion ! but maybe they are diodes ??? Z Greetings, Helmut ... From:
                                        Message 19 of 27 , Nov 6, 2003
                                        • 0 Attachment
                                          Hi Bill,

                                          You are absolutely right !
                                          you don't have to be sorry for your Opinion !
                                          but maybe they are diodes ???

                                          "Z" Greetings, Helmut

                                          ----- Original Message -----
                                          From: <zbendtrack@...>
                                          To: <z_scale@yahoogroups.com>
                                          Sent: Wednesday, November 05, 2003 8:34 PM
                                          Subject: Re: [z_scale] Z scale MRC Transformer modified by MTL



                                          > > Hi All, Call MRC and buy their $8.00 resister pack made for this use. Goes
                                          > > between transformer and track. Bill

                                          > I've not familiar with that MRC product. They may sell a resistor pack, but
                                          > its a very unwise choice for track power, I would suggest.
                                          >
                                          > Since the voltage drop across a resistor is proportional to the current drawn
                                          > through it (Ohms law) the voltage to the track would vary significantly with
                                          > the grade, number of cars pulled, tight turns versus straight track, different
                                          > loco's, etc.
                                        • Helmut Paule
                                          Hi Manfred, I put you on the list, let me know when you are at H&R ? Z Greetings, Helmut ... From: M. Gottschalch To:
                                          Message 20 of 27 , Nov 6, 2003
                                          • 0 Attachment
                                            Hi Manfred,
                                            I put you on the list,
                                            let me know when you are at H&R ?
                                            "Z" Greetings, Helmut

                                            ----- Original Message -----
                                            From: "M. Gottschalch" <afn47583@...>
                                            To: <z_scale@yahoogroups.com>
                                            Sent: Thursday, November 06, 2003 8:02 AM
                                            Subject: Re: [z_scale] Re: Z scale MRC Transformer modified by MTL


                                            > Hi Helmut,
                                            >
                                            > I hope you are still doing good health wise and also in everything else.
                                            > I read your post with great interest so when you get done with the write
                                            > up could you please email me a copy.
                                            >
                                            > Thanks, Manfred
                                            >
                                            > PS. I need to get to the next H&R train open house. It is always a lot
                                            > of fun. Hope to see you there.
                                            >
                                          • Bill Powers
                                            Bill, you made me look at that thing from mrc. It has 12 diodes running end to end. the #s on them is in5406?????? Bill Powers ... From: zbendtrack@aol.com To:
                                            Message 21 of 27 , Nov 7, 2003
                                            • 0 Attachment
                                              Bill, you made me look at that thing from mrc. It has 12 diodes running end to end. the #s on them is in5406?????? Bill Powers
                                              ----- Original Message -----
                                              From: zbendtrack@...
                                              To: z_scale@yahoogroups.com
                                              Sent: Wednesday, November 05, 2003 7:34 PM
                                              Subject: Re: [z_scale] Z scale MRC Transformer modified by MTL


                                              Bill:

                                              > Hi All, Call MRC and buy their $8.00 resister pack made for this use. Goes
                                              > between transformer and track. Bill

                                              I've not familiar with that MRC product. They may sell a resistor pack, but
                                              its a very unwise choice for track power, I would suggest.

                                              Since the voltage drop across a resistor is proportional to the current drawn
                                              through it (Ohms law) the voltage to the track would vary significantly with
                                              the grade, number of cars pulled, tight turns versus straight track, different
                                              loco's, etc.

                                              Keeping anything near a steady speed of the train would require constant
                                              adjustment on the throttle as it goes around the layout.

                                              It's awful easy to just restrict the throttle knob rotation, and enjoy a near
                                              constant speed with the excellent electronic regulation that's inside the
                                              power pack.

                                              Sorry for the difference in opinion.

                                              Bill K.
                                              Houston


                                              [Non-text portions of this message have been removed]


                                              Yahoo! Groups Sponsor
                                              ADVERTISEMENT




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


                                              Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


                                              [Non-text portions of this message have been removed]
                                            • Glen Chenier
                                              ... running end to end. the #s on them is in5406?????? Bill Powers ... this use. Goes ... 1N5406 - This is a standard 3 amp dilicon diode, costs 32 cents each,
                                              Message 22 of 27 , Nov 7, 2003
                                              • 0 Attachment
                                                --- In z_scale@yahoogroups.com, "Bill Powers" <wjpo@c...> wrote:
                                                > Bill, you made me look at that thing from mrc. It has 12 diodes
                                                running end to end. the #s on them is in5406?????? Bill Powers
                                                >>
                                                > > Hi All, Call MRC and buy their $8.00 resister pack made for
                                                this use. Goes
                                                > > between transformer and track. Bill

                                                1N5406 - This is a standard 3 amp dilicon diode, costs 32 cents each,
                                                10 cents in large quantities. data sheet is at

                                                http://rocky.digikey.com/WebLib/General%20Semi/Web%20Data/1N5400%20-%
                                                201N5408.pdf

                                                the voltage drop vs current curve is shown FYI. With 6 in series
                                                each way, at 1/2 amp just about 4 volts constant like they say. Now
                                                we know how not to spend $8.00 ;-)
                                              • Bill Powers
                                                Glen, Thank you. I m going to Radio Scrap in the morning to get some. Bill ... From: Glen Chenier To: z_scale@yahoogroups.com Sent: Friday, November 07, 2003
                                                Message 23 of 27 , Nov 8, 2003
                                                • 0 Attachment
                                                  Glen, Thank you. I'm going to Radio Scrap in the morning to get some. Bill
                                                  ----- Original Message -----
                                                  From: Glen Chenier
                                                  To: z_scale@yahoogroups.com
                                                  Sent: Friday, November 07, 2003 8:59 PM
                                                  Subject: [z_scale] Re: Z scale MRC Transformer modified by MTL


                                                  --- In z_scale@yahoogroups.com, "Bill Powers" <wjpo@c...> wrote:
                                                  > Bill, you made me look at that thing from mrc. It has 12 diodes
                                                  running end to end. the #s on them is in5406?????? Bill Powers
                                                  >>
                                                  > > Hi All, Call MRC and buy their $8.00 resister pack made for
                                                  this use. Goes
                                                  > > between transformer and track. Bill

                                                  1N5406 - This is a standard 3 amp dilicon diode, costs 32 cents each,
                                                  10 cents in large quantities. data sheet is at

                                                  http://rocky.digikey.com/WebLib/General%20Semi/Web%20Data/1N5400%20-%
                                                  201N5408.pdf

                                                  the voltage drop vs current curve is shown FYI. With 6 in series
                                                  each way, at 1/2 amp just about 4 volts constant like they say. Now
                                                  we know how not to spend $8.00 ;-)


                                                  Yahoo! Groups Sponsor
                                                  ADVERTISEMENT




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


                                                  Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.


                                                  [Non-text portions of this message have been removed]
                                                • Glen Chenier
                                                  ... some. Bill ... Bill, These are Digikey prices - still higher than average, but they are fast, handy mail order, datasheets at a mouseclick, and usually
                                                  Message 24 of 27 , Nov 9, 2003
                                                  • 0 Attachment
                                                    --- In z_scale@yahoogroups.com, "Bill Powers" <wjpo@c...> wrote:
                                                    > Glen, Thank you. I'm going to Radio Scrap in the morning to get
                                                    some. Bill
                                                    >

                                                    Bill,

                                                    These are Digikey prices - still higher than average, but they are
                                                    fast, handy mail order, datasheets at a mouseclick, and usually have
                                                    stock. Don't know what Radio Scrap charges, but these are just
                                                    ordinary silicon diodes. Most any type will do, reverse voltage
                                                    rating is not an issue in this application, but the diode current
                                                    rating is important for shorts and for how fast does the power pack
                                                    shut down on overcurrent (derailment/shorts) situations? In other
                                                    words, does the power pack shut down BEFORE the diodes overheat and
                                                    burn out?

                                                    I've avoided the problem on my railroads by designing my own low
                                                    frequency battery operated pulse power packs with instant short
                                                    detect/shutdown/indication/recovery by monitoring current draw per
                                                    pulse without depending on PTC (positive temperature coeficient)
                                                    devices that have much too slow a response for my liking. I've seen
                                                    what can happen to locomotives when the power pack cannot immediately
                                                    detect a short and react instantly to prevent locomotive damage.
                                                    This is the result of nickel-and-diming a product to death by
                                                    marketing-type persons who have no concept of the technical issues.
                                                    Have been there...
                                                  • Jeremy Brandon
                                                    ... Glen, I must comment on your assaults on PTC devices. I assume you are talking about PTCs (resistors that increase their resistance when they get hot) in
                                                    Message 25 of 27 , Nov 10, 2003
                                                    • 0 Attachment
                                                      --- "Glen Chenier" <chenierfam@c...> wrote:
                                                      > In other words, does the power pack shut down BEFORE the diodes
                                                      > overheat and burn out? I've avoided the problem on my railroads ...
                                                      > ... without depending on PTC (positive temperature coeficient)
                                                      > devices that have much too slow a response for my liking.

                                                      Glen, I must comment on your assaults on PTC devices.

                                                      I assume you are talking about PTCs (resistors that increase their
                                                      resistance when they get hot) in series with either the power side or
                                                      output side of a controller. These usually have a very low resistance
                                                      that makes them invisible at currents the controller is designed to
                                                      produce, but which heat up at higher currents (overload) and reduce
                                                      the current flowing. Unfortunately PTCs used like this are rarely
                                                      effective because they depend on their own heating to trigger the
                                                      effect they are supposed to produce, and at best reduce the current
                                                      to a level of equilibrium where the current flowing stabilises at the
                                                      maximum design limit. Result: they take a relatively long time to act
                                                      and do not reduce the current to a safe level. So far I can only
                                                      agree with you.

                                                      But PTCs can also be used in an intermediate stage within the
                                                      controller. I successfully use a PTC as the base resistor of the
                                                      output transistor. Here its effect is amplified by the transistor and
                                                      causes output current to drop to a very small value. My "briefcase"
                                                      controller, now available from Ztrack magazine, has a PTC used in
                                                      this way which drops the current to around 30 mA at overload with a
                                                      maximum temperature of 90C. Its "head" pokes into the hole in the
                                                      transistor so the temperature of the whole PTC/transistor combination
                                                      acts to reduce the current - usually in a second or so.

                                                      So PTCs are fine when they are used properly. Jeremy.
                                                    • Glen Chenier
                                                      ... combination ... In this manner, yes. They work much faster when sensing heat from other components, i ve used them thermally coupled to resistors to
                                                      Message 26 of 27 , Nov 10, 2003
                                                      • 0 Attachment
                                                        >My "briefcase"
                                                        > controller, now available from Ztrack magazine, has a PTC used in
                                                        > this way which drops the current to around 30 mA at overload with a
                                                        > maximum temperature of 90C. Its "head" pokes into the hole in the
                                                        > transistor so the temperature of the whole PTC/transistor
                                                        combination
                                                        > acts to reduce the current - usually in a second or so.
                                                        >
                                                        > So PTCs are fine when they are used properly. Jeremy.

                                                        In this manner, yes. They work much faster when sensing heat from
                                                        other components, i've used them thermally coupled to resistors to
                                                        enhance their usefulness. And they are useful as 'resettable' fuses
                                                        and preventing major damage such as fire. The key is "used
                                                        properly". By themselves they take longer to react and can allow
                                                        damage to occur, although much depends on how prone the load is to
                                                        damage.

                                                        But they also take time to recover once the short is cleared; a fast
                                                        acting electronic current sense works immediately for both shutdown
                                                        and recovery and can provide a visual indication of a short. And
                                                        nothing at all gets hot or even warm, not even those thin wires
                                                        through the roadbed to the rails.
                                                      Your message has been successfully submitted and would be delivered to recipients shortly.