KATO 20-605 Signals: Compatibility issues with PowerPack SX?

[Yavianice]

I have discovered something perplexing:

 

Connecting the KATO 20-605 Signal makes my trains go faster than when it is not connected. Here is the full story:

 

I have a large Oval, connected with 4 feeders to my Power Pack SX. In that Oval I have a point that leads to a deadheading storage yard. On that siding I have a KATO 20-605 signal. When I switch my point so the Oval is completed, the train goes SLOWER, but when the point is switched to the deadheading storage yard/signal it goes FASTER.

 

I tried the following:

 

• Different KATO PowerPack SX: All same issue
• Different KATO 20-605 signals: All same issue
• Powering the KATO 20-605 signal or leaving it off: doesn't matter
• Connecting different KATO 20-605 signals at the same time: Does not increase speed (aka infinite energy isn't solved)
• Removing all feeders except one: Same issue (though the difference is less drastic; the train takes off when all feeders are connected and the point is set to the siding with the signal)
• Placing a 20-605 signal in the loop as well as on the siding: Train runs consistently (aka: no problem at all) and it runs faster than if no signals are connected.
• Tried KATO PowerPack S (without PWM) with all above scenarios: Train runs consistently (aka: no problem at all).

 

For fun I also tried a piece of KATO track that has a TOMIX sensor embedded in it, no change. 

 

This makes me believe that there is some compatibility issue with KATO 20-605 and PowerPack SX. But that it goes FASTER when the signal is connected is truly baffeling me.

 

Anyone know what is going on?

[inobu]

The train speed increases as voltage increase.

 

So, the speed differences is based on the voltage at the track.

You should take voltage readings at each point on the layout to identify each voltage levels.

 

 

 

Not being able to see the layout plan its hard to say.

 

 

 

[cteno4]

That’s an odd one! So just to be clear, if a train is going around the loop and you put the yard turnout to the yard the train speeds up w/o doing anything else, correct? Same happens if now power is fed to the signal (ie signal totally unplugged) correct? I could some now see power some how leaking in from the signal. Maybe vacuum energy? Cold fusion?

 

it must be something with the pwm as regular just plain voltage regulation does not show the effect. I’ve never played with the signal mech so don’t know how it might do this, but it’s really odd as it’s like the signal track being there is increasing the pwm power pulse lengths.

 

weird.

 

jeff

[Yavianice]

Yup, my train magically goes faster when I switch the point to the storage yard, and slower when back to the oval, even if the signal is not powered.

[brill27mcb]

I have experienced a similar thing happen, also with a PWM power supply. In my case, though, it was when I added a Hornby Arnold tram to a layout.

 

I was running a small Tomix double-track tram oval, with both tracks powered from a single Tomix PWM power supply. One track had a Kato/Lemke 2-axle German tram running. When I put the Hornby Arnold Duewag GT6 tram on the other track, I expected the first tram to slow down a bit, since the power supply was dealing with a heavier electrical load. Instead it sped up dramatically. It went back to normal when I removed the Hornby Arnold tram from the other track. (The Hornby Arnold tram was the non-digital version, but if I remember right they come with a substitute board plugged into the digital socket to complete the circuitry.)

 

I have been at a loss to explain it, but I suspect something in the Hornby Arnold tram was adding a capacitive effect to the whole layout, basically filling in the no-voltage gaps between the pulses of power from the PWM supply.

 

You found out, as I did, that replacing the PWM power supply with a more traditional DC (non-PWM) supply stops this strange effect.

 

Rich K.

[cteno4]

Rich,

 

that sounds like a potential explanation with a capacitor effect filling in the gaps some. With a higher frequency pwm it wouldn’t take much capacity I’m guessing (and it is just a educated guess I’ve never played a ee on tv).

 

jeff

[Yavianice]

6 hours ago, brill27mcb said:

I have been at a loss to explain it, but I suspect something in the Hornby Arnold tram was adding a capacitive effect to the whole layout, basically filling in the no-voltage gaps between the pulses of power from the PWM supply.

The next question is: is this a bad thing?

[brill27mcb]

If you can't use your Kato 20-605 signal and the Kato SX power supply together on your layout and you want to, then yes it's a bad thing.

 

With the growing electronic sophistication of model trains along several diverging paths of development, unforeseen issues crop up. We have gone from basic rectified DC and wire-wound rheostats in the old days to transistor throttles, then PWM supplies, and then on-board digital controls. At the same time, slow-reacting open frame motors have been replaced by higher efficiency can motors, coreless motors that can easily overheat, and micro-motors from cell phone technology. Things that were designed simply in the past, expecting fairly constant power from the perspective of a bulky motor or a resistor-capacitor time delay circuit, can now act up when PWM repeatedly and rapidly turns the track power off and on. Digital decoders, originally designed expecting constant track power, had to be revised to remember their state when power is interrupted, or need "stay alive" circuits to handle brief power losses.

 

I would not be surprised if we see a new Kato signal released in the future, and the present design retired. As the SX overtakes the S power supply in the marketplace, Kato will have to deal with this issue of unintended incompatibility of their products.

 

I don't know of any fix for my Hornby Arnold tram issue, so I use the older Kato S supply with both my Tomix and my Kato track layouts and live without the constant lighting benefit of newer PWM-based supplies. I feel safer using the simpler full-wave rectified power instead of PWM when running a variety of powered models. I also keep a careful eye on trams with advanced electronics onboard when I run them on my Tomix TNOS setup, which is PWM-based.

 

I was concerned about how well Kato's tiny 3V tram drive in the Portram and Hiroshima LEX trams would work and survive using PWM power, but it turns out that Kato's Hiroshima tram starter set includes the SX supply, so apparently the Kato people are not concerned about it. Now I wonder how well the new Kato "slotless" motor will play with the various types of power - I guess we will see.

 

Rich K.

[inobu]

In all actuality you need an O-Scope to see the Pulses.

The voltage reading will give you a comparison of the two sides.

 

The 20-605 is an analog device where as the PWM is the basis for a Digital signal.

 

The 20-605 has a pcb installed in it. As stated a form of capacitance can be effecting the width of the pulse

therefore increasing the applied voltage duration which increases speed.

 

This is a good example of what the O Scope will show

 

http://michael-buschbeck.github.io/assets/2013-11-10-rigol-ds1052e-oscilloscope-pwm/scope-screen-measure.gif

 

The pulse width increase is the increase in applied voltage.

 

the slow side would be the narrower width.

 

Edited January 3, 2022 by inobu

[Yavianice]

3 hours ago, brill27mcb said:

If you can't use your Kato 20-605 signal and the Kato SX power supply together on your layout and you want to, then yes it's a bad thing.

 

Well, I can use it, the trains just run quicker. I always assumed KATO 20-650's PCB was only connected with the cable that supplies the Signal with power, and not with the actual track (besides the occasional times the sensor is tripped by a train running over it. Running a train over the signal doesn't result in strange behavoir btw). I power my KATO 20-650 with the S power pack which I use for all accessories (station lights and the signals).

 

But I wonder if it will damage the signals or, more importantly the train, over time during regular use now that I have the signal embedded in my track is the question. I won't run trains at 100% constantly, if ever...

Edited January 3, 2022 by Yavianice

[inobu]

I power my KATO 20-650 with the S power pack which I use for all accessories (station lights and the signals).

57 minutes ago, Yavianice said:

I power my KATO 20-650 with the S power pack which I use for all accessories (station lights and the signals).

 

That's why I said its hard to say without seeing the layout.

 

If you are using the S Power Pack to drive the 20-605 and you track with the SX. Then most likely the S unit is feeding power via one of the rails.

 

try reducing the S Power Pack to a lower voltage.

[Yavianice]

1 hour ago, inobu said:

That's why I said its hard to say without seeing the layout.

Can't give you a schematic because I have yet to discover a track layout manager that supports the 22.5 degree curve which is superelevated on BOTH sides (Unique Kato Piece included in the V12 set which does not have a product number).

 

1 hour ago, inobu said:

If you are using the S Power Pack to drive the 20-605 and you track with the SX. Then most likely the S unit is feeding power via one of the rails.

What I described above happens when the Signal is disconnected (non-powered) but included in the track. There is no difference between the signal being powered and non-powered.

 

If I have some time I will create a test track (small oval) for demonstration purposes. Though I guess it's easier to invest in a rolling road for model train loco's; I'll look into that.

[inobu]

The basic setup at the bottom uses a single common grounded circuit.

 

I read this to be the configuration. Where the S is powering the signal and a SX the track.

There is a connection between the track and PCB

 

This images shows the track connecting to the PCB. There is a lot

more going on.......

 

 

 

[Yavianice]

Yes, the sensor is connected to the track, whenever the trainwheels touch the sensor the signal turns red. but I don’t think it means that the Power Pack S feeds into the track via the signal, does it?

[cteno4]

Ahh yes more to it. The signal pcb must be acting as a capacitor to lengthen the pulses as the speed up happens even if signal is not plugged into the aux dc power.

 

jeff

[inobu]

2 hours ago, Yavianice said:

Yes, the sensor is connected to the track, whenever the trainwheels touch the sensor the signal turns red. but I don’t think it means that the Power Pack S feeds into the track via the signal, does it?

The test would be to look for continuity between the S and SX. 

 

I would guess that the PCB -R is common to the input -V.

If that's the case the S V+ is feeding the circuit when SX R+

is going to -0.

 

Doing what Jeff is saying

 

 

Edited January 4, 2022 by inobu