Railpower 1300 modified for Z scale by Micro Trains

[dieselfan1]

After buying three of these I hear they will ruin my AZL locos. I have not run anything yet and not even sure I want to now. What's the concensus here?

[thomasjmdavis]

I was surprised MTL had these available.
https://micro-trains.com/index.php?route=product/product&product_id=626

But, you came to the right place...
@Gozer the Gozerian
@ztrack

[randgust]

I'm an N guy but I've done Nn3 by converting AZL mechanisms to 3' Nn3 projects, so I kinda get it.

And I've done enough Nn3 on various chassis.   My experience is that Z, going back to Marklin, runs at a lower maximum voltage, like 9V.   And it's really tricky to control, and the number of coreless motors out there like on AZL with extremely low current draw make a conventional rheostat relatively useless.    Ohms law will get you.

So the potential for damage from reputed voltage spikes on anything that's attempting to do some kind of wave-control DC rather than resistance control is real.   It could happen.   I don't have one of these but I agree with the theory that it could.   I found some of the reports you probably have.   And it may be only if there's a DCC board in there that's more sensitive.   I haven't done that - I really try to avoid running anything with a decoder board on ANYTHING but pure DC, resistance controlled.  I blew a Bachmann decoder with a transistor throttle on DC.

Now for the solution I found on all manner of coreless tiny motors - the BlueLine Snail Z controller.   It's basically a 9 volt battery in a box that has a wave-form control.  It's tiny.  But it's the only thing I've ever seen that can control a Rokuhan chassis down to manageable speed, creep an AZL, run whatever, and also have enough 'beef' to work as a great quick-test throttle for conventional N scale stuff - I use it to QC test my Ttrak modules with an adapter plug.

I'd tried piling on all manner of rheostats and additional resistors on a lot of the coreless motor drives from Japan, without much success for slow speed, this actually worked very well.

[peteski]

We had a lengthy discussion about the MRC 1300s few years back when rapido trains stated that they could damage the ESU decoders in their models (N scale) and they would honor the warranty if the model was being operated on DC using MRC1300 throttles.  The takaway of our forum's electronics  guys was that these simple throttles can supplu in excess of 20V peak (they use unregulated and unfiltered pulse DC).

But that type of voltage should damage motors in pure DC locos (which have not DCC decoders).

I didn't even realize there was a Z scale version. I really not sure what to tell you as I don't know what modifications were made by MTL.  They added a resistor to limit the upper voltage, but that doesn't eliminate peak voltages on the throttle's output.  If the Z scale models are DC-only, do they use standard DC motors with iron armatures, or coreless motors?

I wouldn't want to give an answer either way without having much more technical info.  This is the first time I have heard this warning (but I'm not up on Z scale models).

[thomasjmdavis]

According to the MTL description at the link I provided above,

This MRC powerpack has been externally modified for operating Z Scale locomotive 10V D.C. Max. By Micro-Trains Line Co. For Micro- Trains Locos 10V D.C. and Marklin Locos 8V D.C. #500-195

[pmpexpress]

We had a lengthy discussion about the MRC 1300s few years back when rapido trains stated that they could damage the ESU decoders in their models (N scale) and they would honor the warranty if the model was being operated on DC using MRC1300 throttles.  The takaway of our forum's electronics  guys was that these simple throttles can supplu in excess of 20V peak (they use unregulated and unfiltered pulse DC).

But that type of voltage should damage motors in pure DC locos (which have not DCC decoders).

I didn't even realize there was a Z scale version. I really not sure what to tell you as I don't know what modifications were made by MTL.  They added a resistor to limit the upper voltage, but that doesn't eliminate peak voltages on the throttle's output.  If the Z scale models are DC-only, do they use standard DC motors with iron armatures, or coreless motors?

I wouldn't want to give an answer either way without having much more technical info.  This is the first time I have heard this warning (but I'm not up on Z scale models).

Having stocked and sold some of these Micro-Trains Line modified power-packs ions ago (i.e., when I was still selling Z-Scale trains), the external modification was simply a stop that limited how far a user could turn the throttle dial and mechanically reduced the pack's 15 volt maximum to 10 volts.

From what I have read in the past, AZL and Marklin Z-Scale locomotives have a maximum voltage rating of 8 volts, while the Micro-Trains Line Z-Scale locomotives have a max rating of 10 volts.

Based upon an assumption that the MRC Railpower 1300 has a discrete pulse power function, unlike many of the earlier production MRC power-pack releases, the 1300 has no switch for turning the pulse power.

The bigger issue is that if the power-pack has a maximum output of 15 volts, a throttle stop will make no difference should said power-pack still be generating constant 15 volt pulses.

[peteski]

For all the gory Railpower 13000 testing and analysis details, see https://www.therailwire.net/forum/index.php?topic=44170.0

[mmagliaro]

The thread Peteski linked you to is the one with all the data.
If MT modified that 1300 to have a maximum of 10v instead of 15, that's good.  But be aware that the 1300
is a simple DC circuit that lets the full-wave pulses go through to the output with a few components in there to
somewhat control when they go out (at what throttle levels).  I won't go into more detail than that.
Suffice it to say that at low current outputs (and single N or Z engine certainly counts as low), the stock 1300
has peaks as high as 25v at full throttle.   I don't know what MRC actually did inside there, but I would bet you'll see peaks
proportional to the original 1300, meaning 10/15 x 25 or about 16.6v. 

The trick is whether the duration of those peaks, and the amount of time you run high enough on the throttle dial,
overheat the motor?   I cannot answer that. 

I can tell you that that thread Peteski linked also discusses mods I made to that throttle to limit the peaks to somewhere between 19v and 21v depending on load.  And the zener I chose could easily be altered to limit the peaks down to something like 12v for Z scale.  This is peak, not RMS.   The RMS with a 12v peak limiter in there would probably be something around 8.

Altering the circuit, instead of just mechanically limiting how far you can turn the dial, is a much better solution because it gives you the full rotational control range.

[Rivet Miscounter]

From what I have read in the past, AZL and Marklin Z-Scale locomotives have a maximum voltage rating of 8 volts, while the Micro-Trains Line Z-Scale locomotives have a max rating of 10 volts.

Minor point of clarification here...   Newer AZL stuff is not 8 volts.  Only certain older models have that characteristic....newer AZL locos are 12 volts. (or, at least stated to work with 12 volts)

I was the one that referenced the Railwire discussion about the Railpower 1300's in a post on AZL's forum.  The important context is that the original thread posed the question of "Best Controller for Z to purchase", meaning if you're buying something new.   And from that, I stand by my statement that I would not recommend buying a Railpower 1300 for Z.  AZL also alluded to them getting worse with age, and the MTL mod for these was done 20-ish years ago now.  I have no idea if that is a thing, just adding that tidbit.

But, full disclosure...  I have one of the MTL-mod'ed 1300's, have used it, and have not damaged any locomotives to my knowledge. (I actually have an unmodified one as well, that I purchased well prior to learning about the odd spike situation.)  I would be very concerned about running MTL SD40-2/GP35 locos on an un-modified one, because they run extremely slow in my experience and the inclination is to bump the throttle up.   (as an aside, I intend to sell both, not because I'm deathly afraid of them smoking my AZL stuff, but simply because I have other options now and it's just a space issue....the Rokuhan packs are nice and compact.   And I don't really do anything in DC in N as almost my entire fleet is DCC/Sound.   I'm probably 2/3 DCC in Z too.)

But in the end, I still wouldn't recommend buying one for Z.  Even mine.   

[dieselfan1]

I plan on running my trains at a realistic 25 mph or so. It will never see anything faster than that so I should be OK I guess.

[nscaler711]

The only thing I will suggest running Z scale, is Rokuhan controllers either the RC-02 or RC-03. They appear to have some PWM built in for constant interior lighting. They can be used as a battery operated throttle as well.
If you want to plug into the wall you'll need the A028 AC adapter as well.
 
I have the RC-02 as I did not need the turnout throws while I use MTL track, Has been going strong for about 5 years now.

RC-02
https://www.ztrackcenter.com/RC02

RC-03
https://www.ztrackcenter.com/RC03

A028
https://www.ztrackcenter.com/A028

You can also try Plaza Japan for these as well, shipping is a little longer (unless you use DHL which I highly recommend) but can be slightly cheaper.

As far as the 1300 goes, I would not trust it with anything Z scale regardless of the modifications. 

[mmagliaro]

Can I ask what does having PWM (in the Rohukan throttles) have to do with constant lighting?    I suppose if your engine and car lighting have nice big capacitors on them, and rectifiers to keep the cap charge from leaking back into the track, maybe the brief pulses at lower speed PWM would still be enough to charge up the caps and make the lights pretty bright even though the motor is barely moving.  Is that it?

As for the 1300, I wouldn't use it at all unless it was properly modified, and that means better than just putting a pin on the dial so it can't be turned up too high.  The zener diode mod I did on the one referenced in that big long thread guarantees you an absolute maximum possible
voltage out of that throttle, and that's really what you want if you want to protect a delicate motor.  You can hard-limit it to 15, 12, 8, whatever you want.  Otherwise, honestly, the 1300 isn't bad at all.  It's  a decent simple power controller with a nice pulse in its output.  It's just that darn top voltage that has to go.

[Chris333]

The Rohukan throttle just has a little clicking stopper on the dial that you can set so the power isn't turned all the way off. I think this is the constant lighting thing. You turn it down, the train stops, but the light stays on?

Seen at 3:38 in this video:

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lol actually I'm more confused now as to how it works...

[peteski]

It is likely a circuit similar to those constant lighting circuits popular in back in the day ('60s and '70s).  Basically it is a high frequency (20kHz?) 12V amplitude AC sinewave signal fed to the track, along with standard DC variable voltage.

Since it is a symmetrical AC signal, the motor is not affected by it - it only sees the standard variable DC throttle voltage. The motor only sees the standard variable DC voltage, so it runs as it is supposed to.  However, incandescent bulbs will "see" the high frequency voltage, so they will glow, regardless of any DC voltage also present on the track.  Even when the train is stopped (zero volts DC), the bulbs sill still glow.

I suspect that is what the Rokuhan throttle does.  All it has to do is to switch from the typical single polarity PWM pulses (which runs the motor) to a symmetrical bi-polar wave. The motor will not run, but any lights connected to the track will see that voltage and glow.

[nscaler711]

It is likely a circuit similar to those constant lighting circuits popular in back in the day ('60s and '70s).  Basically it is a high frequency (20kHz?) 12V amplitude AC sinewave signal fed to the track, along with standard DC variable voltage.

Since it is a symmetrical AC signal, the motor is not affected by it - it only sees the standard variable DC throttle voltage. The motor only sees the standard variable DC voltage, so it runs as it is supposed to.  However, incandescent bulbs will "see" the high frequency voltage, so they will glow, regardless of any DC voltage also present on the track.  Even when the train is stopped (zero volts DC), the bulbs sill still glow.

I suspect that is what the Rokuhan throttle does.  All it has to do is to switch from the typical single polarity PWM pulses (which runs the motor) to a symmetrical bi-polar wave. The motor will not run, but any lights connected to the track will see that voltage and glow.

Pretty much sums it up, granted I have no way of actually testing one on its voltage range while it "pulses." I could probably tear one apart for the tech gurus here, but that's all it basically does.
Unlike some cheaper and older PWM throttles/ DC motor controllers, the motors do not emite a buzzing sound like you would hear with a DC locomotive on DCC.
Also with that Secondary dial, you can have it off, or set to be a minimum voltage that a locomotive may start to move.