Railpower 1300 testing

[nkalanaga]

Peteski:  No, I do not consider "setting standards" "regulation".  Standards are a good thing, and as long as products are properly described and labeled, so that consumers can tell what standards they follow, if any, non-standard products are fine. 

As an example, if I was modeling a Russian railway in N scale, my track wouldn't be 9 mm gauge, and I would like to be able to buy "non-standard" wheelsets for my gauge.  But they should be clearly labeled, both so that I can find them, and so that "standard N gauge" modelers won't buy them by mistake.

We actually have that problem in N scale today, with "Nn3".  Most modelers use Z gauge, 6.5 mm, track, and the manufacturers make wheels to match that gauge.  But it is NOT 3-foot gauge in 1:160 scale, and if someone tried to actually model true Nn3, the wheelsets sold as Nn3 wouldn't fit their accurate track.  O scale has had the same problem for decades.

[peteski]

Who said anything about "official warnings"?

Given that we still don't have any technical specifics from Rapido, how might you suggest to best address this situation?
What information (and in what format) might be provided to the consumer (who may not have (or need) any technical background) to help ensure that they can select a dual-mode loco and a DC power pack that are compatible with one another?

. . .then it's incumbent on Rapido to verify that their decoders are compatible with DC power packs and, if necessary, furnish a listing of those compatible power packs.  If that is not feasible, then they should provide a specification for the maximum (peak) input voltage that their decoder can tolerate without damage. Likewise the power pack manufacturers should  be able to specify the maximum (peak) output voltage that their power packs can produce.

Ok, maybe not exactly a warning, but really detailed electric specs and rigorous compatibility testing.  Do you own one of the H0 locos affected by this alleged problem?  Maybe there are specs included in the enclosed manuals?  Maybe not . .  The MRC 1300 has its electrical ratings printed on its case (whether they are accurate is another story). As I understand the 1300 was designed before DCC decoders were widely used and nobody ever considered that it would be used to power delicate electronic decoders inside models. For goodness sake, we are talking about model trains not some life-support medical equipment.

I'll say again: We have alleged incompatibility of one DC throttle with one DCC decoder.  And again, have you heard of the 1300 or any other DC throttle damaging any other DCC decoders?

I guess we could can go at it over and over again, but the bottom line is that this discussion is not going to make any difference.  Lets just boycott both manufactures until they fix this problem. 

Ron, I *AM* a bot! 

[Point353]

I'll say again: We have alleged incompatibility of one DC throttle with one DCC decoder.  And again, have you heard of the 1300 or any other DC throttle damaging any other DCC decoders?

Again, the claim by Rapido that the MRC 1300 produces some sort of "spikes" that are damaging the dual-mode decoders used by Rapido is what we're trying to investigate. We seem to have quantified the output of the 1300 and in so doing have not observed any alleged "spikes", nor is there anything obvious in the circuit configuration that might give rise to them. We have seen that the peak output can reach up to about 25V.

Again, Rapido first identified the issue with the decoders in their HO RDC models. The NMRA standard indicates that an HO decoder should withstand a DC input of up to 27V.  Likewise, there don't appear to be any similar reports from other loco or decoder manufacturers. What does that suggest as to where the problem might lie?

Further, it seems rather telling that through 10+ pages of this thread there hasn't been a peep out of Jason from Rapido.

[up1950s]

Again, the claim by Rapido that the MRC 1300 produces some sort of "spikes" that are damaging the dual-mode decoders used by Rapido is what we're trying to investigate. We seem to have quantified the output of the 1300 and in so doing have not observed any alleged "spikes", nor is there anything obvious in the circuit configuration that might give rise to them. We have seen that the peak output can reach up to about 25V.

Again, Rapido first identified the issue with the decoders in their HO RDC models. The NMRA standard indicates that an HO decoder should withstand a DC input of up to 27V.  Likewise, there don't appear to be any similar reports from other loco or decoder manufacturers. What does that suggest as to where the problem might lie?

Further, it seems rather telling that through 10+ pages of this thread there hasn't been a peep out of Jason from Rapido.

It's Easter , maybe somebody has eaten his peeps . Or there is a legal suit and his lawyers told him to say nothing .

[metalworkertom]

"Maletrain:  You mentioned some of the modern PWM throttles. We have not tested any of those here (except for a vintage MRC unit which seem to have max voltage within acceptable range).  I suspect that truly modern DC throttles (which use BEMF) have their voltages well within acceptable range."
I did receive and build from kit one of Ken Stapleton 's hand held kits . Model 852B I did get it tested . It's voltages are well below any others. I didn't test it with the 60ma load as I didn't have the bulb with me at work. I used the  fixed AC from the Tech II 1440 which is 18 vac. Note the photo with 1.3 volt or so is the throttles lowest setting so I'm going to have to do something about that.

[jagged ben]

I did not realize this!  That means that the NMRA spec's "voltage measured at the track" is, in fact, the peak - the highest voltage, even if instantaneous, that should be on the rails.
So the 1300 is over spec on that voltage.   

...

I do not agree that the 1300 violates the NMRA standard.  Here's the actual sentence at issue: 

Digital Decoders intended for "N" and smaller scales shall be designed to withstand a DC voltage of at least 24 volts as measured at
the track.

The point I've been making since I chimed in on this thread is that that kind of statement must refer to the RMS voltage, not the peak voltage.   I don't believe there's any industry in which a standard like that, stated without further clarification, would refer to peak waveform voltage and not RMS voltage; a peak waveform voltage rating would have to be clearly clarified as such.  Moreover, as I already said, for that standard to have any meaning for Joe Hobbyist, it has to refer to what is measured by a quality volt meter, not an oscilloscope.

The standard is oddly written, but since DCC is an AC waveform, the standard's referring to DC voltage must mean that decoders that have an analog mode will not be damaged at 24VDC RMS. 

And to repeat, a powerpack that delivers a peak voltage that's 5% higher than the standard and an RMS voltage well below that is not failing to meet the standard.  The decoder that gets damaged by that powerpack is failing to meet the standard.

As far as OFFICIAL WARNINGS, I'll repeat the point I made above:  It seems to me that lots of manufacturers could do a better job of being more upfront and transparent about the voltage ratings of their products.  I agree with Pete, we don't need 'Warnings' so much as proper labeling.  But it would be great if decoder manufacturers put both the RMS voltage rating and a peak voltage rating on their products.  I suspect that there are actually quite a few N scale decoders that don't meet the NMRA standard, and modelers have every reasonable expectation to be warned of that.  In any non-hobby electronics consuming industry, the current paltry state of product labeling we are experiencing would, in my opinion, be quite unacceptable. 

[peteski]

Without knowing what the max voltage specs are on those damaged Rapido decoders (and knowing wheter that info was even provided somewhere with the affected Rapido model, this has become a pointless discussion.

As I already mentioned couple of times in this thread, ESU does provide the voltage specifications for their generic decoders (in the decoder manual), and for all but the micro version of their decoders, the max allowable voltage is well above what the 1300 supplies (even peak to peak).  The ESU micro decoders max voltage is right around the peak voltage of the 1300 throttle.  But I have no idea what decoder design (standard or micro) was used on Rapido decoders.  Again, without having more specific info about the decoder's voltage rating, this discussion doesn't make sense.

[Point353]

It's Easter , maybe somebody has eaten his peeps .

Glad to see someone noted that.

Or there is a legal suit and his lawyers told him to say nothing .

I was wondering that same thing.

So what evidence is there to submit?
The owner's manuals for the MRC 1300 and 1370 define the output as 15VDC.
http://www.modelrectifier.com/v/vspfiles/resources/dc-ac/Rail%20Power%201300%20AA300.pdf
http://www.modelrectifier.com/v/vspfiles/resources/dc-ac/Rail%20Power%201370%20AA370.pdf

If, for example, we go the support page for the Rapido HO FA-2/FPA-2, there are links to the Rapido generated instruction manual and an ESU supplied instruction manual for their ESU LokSound deecoder.
https://rapidotrains.com/wp-content/uploads/2017/09/Rapido_HO_FA2_En.pdf
https://rapidotrains.com/manuals/51980-ESU-LokSound-Manual.pdf

The ESU manual specifies "track voltage" as "27V maximum."
(No one indicates if these are supposed to be peak or RMS values.)
Yet, the Rapido manual warns against the use of the MRC 1300 and 1370 or "any other 'trainset' DC controller."
On what technical basis, then, does Rapido make that assertion, other than coincidence?

Is there more to the story that @rapidotrains is not revealing?

[mmagliaro]

This is only tangentially related, but...

Does anyone here have an MRC 1370 (not a 1300) that they would be willing to let me open up and scope?
I'd also like to know when you bought it and if it was new when you bought.  I'm investigating something.

[Doug G.]

This sentence/spec. doesn't make sense, in context, anyway:

Digital Decoders intended for "N" and smaller scales shall be designed to withstand a DC voltage of at least 24 volts as measured at
the track.

The way it's worded, a decoder has to withstand a DC voltage of 24 volts or higher. It should withstand 100 volts, too.

Doug

[mmagliaro]

This sentence/spec. doesn't make sense, in context, anyway:

Digital Decoders intended for "N" and smaller scales shall be designed to withstand a DC voltage of at least 24 volts as measured at
the track.

The way it's worded, a decoder has to withstand a DC voltage of 24 volts or higher. It should withstand 100 volts, too.

Doug

I know how you are interpreting that sentence, but I think it's clear what they meant.  They did not mean it had to withstand "any voltage of 24 or more".   The modifier "or higher" is clumsily placed in the sentence.

It means the decoder must withstand a DC voltage of 24 or more - or in other words,  at least 24v.    If it withstands 24, it meets the spec.  If it can withstand 50, it meets the spec.  If it can only withstand 23, it does not.

[nkalanaga]

If "spikes" are the problem, then there's nothing practical that can be done to protect the decoder.  I've gotten some nasty shocks from my rails with all power turned off at the wall, just by walking across the carpet on an unusually dry day.  Since static sparks such as that can reach thousands of volts, and are a well known threat to electronics, it looks like people should be frying their decoders daily.

For what it's worth, I'm still strictly DC, and the sparks don't seem to hurt motors, light bulbs, or LEDs with resistors.

[peteski]

For what it's worth, I'm still strictly DC, and the sparks don't seem to hurt motors, light bulbs, or LEDs with resistors.

Exactly.
A little over-voltage or some voltage spike does not harm those older simple DC models. But DCC decoders are full of miniature sensitive electronic components that were not designed to work with older DC throttles with loose tolerances.

However the puzzling thing about 1300 is that except for higher-than-expected maximum RMS and peak voltages Max did not observe any "true" spikes. Looks at the schematic Max created I also do not see any possible sources of "true" voltage spikes in that circuit when it is supplying power to a DCC decoder.

[Point353]

If "spikes" are the problem, then there's nothing practical that can be done to protect the decoder. 

Sure there is.
A wide variety of components is available to suppress voltage transients.
Here is one example: http://www.vishay.com/docs/48316/48316.pdf

[strummer]

For what it's worth, I'm still strictly DC...

...and here I thought I was the only one... 

Mark in Oregon