Triang Locos with TTS Sound?

[Forum-1211528]

/media/tinymce_upload/1fae862851a5b78881dc71e575e78e7d.jpgI have the Triang R751 class 37 in BR Blue it has an XO4 motor and with Hornby announcing a TTS sound chip for a class 37 i wanna put this in my old faithful as i love this loco and yes ive got modern ones with DCC already but i think with sound as theres plenty of room for the DCC chip and speaker then once this comes out next wear i should fit TTS sound to the Triang Class 37!

[Forum-1211528]

/media/tinymce_upload/3a2e71dfa1346bc16ed8b941b9551cdc.jpg/media/tinymce_upload/be0e1e39330d98e4152e158e13c822d4.jpgDo i attempt the unthinkable i have a Triang Princess from the fifties she runs so well and very powerful should i try and fit a Princess tts chip to her shes my favorite old steam loco as id love to see her with this on board as there is room in her for the the chip and speaker and she doesnt have SYNKROSMOKE unit on board as that would kill the DDC chip in its tracks i think i want her with TTS sound this will be great as i have to say this loco was made in Margate in 1954!

[Forum-1211528]

/media/tinymce_upload/11f9cc91753eb43207e0dffec72502ef.jpgDo you like me have tucked away a number of Hornby 80s A4s as with the TTS sound chip and these locos have a Ringfield motor you can install the chip and speaker in your 80s A4 so you can do that and enjoy these classic locos running with sound so lets all get them chipped in 2017!

[Forum-1211528]

/media/tinymce_upload/f5bc9963766e274827cc6ac60e5a6efe.jpgDo you have the R157/158 Triang dmu on your layout they were done in verious forms from the 1950s up to the 1980s in BR BLUE so with these TTS sound chips coming out for the Ex Lima version of this dont ya think converting the Triang one would be a great idea as theres plenty of room on board the DMU for the speaker and chip and really it should work but the XO4 motor is the main problem here so who thinks the Triang Met Cam 101 can be converted to TTS SOUND?

[2e0dtoeric]

With detemination and know-how, most loco's can be converted - BUT - you need to know the stall current of these older motors. TTS decoders are intended for use in modern loco's, the motor of which has a much lower stall current demand.

The XO motors may well fry the decoder.

[96RAF]

As there seem to be a good few people who would like to run their old locos with heavy current appetites using lightweight decoders such as TTS I wonder if one of our experts can dream up a way of using the TTS decoder as a sound board and motor control with an electronic beef-me-up system to provide the extra motor current...maybe a voltage regulator from the track pickups to provide the beef with a 'relay' operated by the motor pwm telling it what to do.

Rob

[Fishmanoz]

To repeat what 2e0 has said, and add some detail, this will only be an excellent idea if the locos' stall currents don't exceed 800mA.  The current capability of the TTS chips is stated as 800mA (motor plus function outputs), 1Amp for short periods (no function outputs).  If the motor in the locos exceeds this, you will blow the chip.

 

You need to run the loco flat out against buffers briefly and put an ammeter, or your multimeter on amps, in series with the track to measure the current.  First make sure your current range will handle at least a couple of amps.  If that comes up at less than 800mA you will be ok.  If not, you run the risk of blowing the chip.  It will be less in normal running, it's just the stall that may be a problem.  Also, it will depend on what shape the motors are in, particularly if the magnets have weakened with age as this increases the current needed to run them.

 

Interesting thoughts on the current beef-up Rob.  It would be a matter of a DC to DC converter using the smoothed PWM decoder motor output as its input I would think.  Reproducing the PWM output at higher current would be more difficult I think, even if you are sacrificing some of the DCC benefits by doing it DC.  Chris?

[Howbi]

Would an 800mA fuse in the motor connection protect the Decoder?........HB

[Chrissaf]

Reproducing the PWM output at higher current would be more difficult I think, even if you are sacrificing some of the DCC benefits by doing it DC.  Chris?

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Perhaps something like this with a bit of modification, offered purely as a theoretical concept for discussion. The 12 volt rail would be the rectified DCC track supply (15V) via a dedicated bridge rectifier (i.e not the one inbuilt on the decoder). The decoder motor PWM output providing the H bridge PWM 1 & 2 control input. Pretty standard H bridge motor control circuit taken from Internet. It uses four Mosfets in an H bridge to provide high current reversible motor control that would switch on and off in sync with the PWM input. Note the PWM switching inputs, these would be derived from the DCC decoder Orange and Grey wires that are themselves a PWM waveform, perhaps with an element of additional interface componentry.

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Before someone asks, no I would not be interested in developing the idea further. I just offer this post to show that the outlined requirement discussed in the previous posts has a potential feasible solution that is an all semi-conductor switched solution without electro mechanical relays etc. that retains the PWM motor control function.

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/media/tinymce_upload/b54b98a56e69a7e9392628e313c97b53.jpg

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Mode of operation: Basically, when PWM 1 is positive and PWM 2 is negative. Two of the diagonally opposite Mosfets are on (the other two diagonal Mosfets are off). The motor drives one way. When the PWM 1 & 2 inputs are reversed, the diagonal Mosfets flip their on and off status and the motor drives in the other direction. The PWM mark space ratio of the PWM 1 & 2 inputs would be replicated in the Mosfet switching ratio, thus retaining the PWM motor control.

[96RAF]

When I said 'relay' eralier I intended a fully electronic solution not a mechanical relay. The problem as I saw it was PWM in and PWM out as well as it having to be reversible.

 

The idea arose when thinking about how GoWest has successfully miniaturised his live steam electronics and with modern electronics hardware such as Chris has outlined cheap and easily sourced and the fact these early diesels have bags of room to spare I reckon the idea will fly.

 

If someone could make it so it was an encapsulated block with two in and two out solder pads, the conversion would be a doddle even if a socket was being installed.

Rob

[96RAF]

Edit timed out...

...plus two pickups from the wheels for the extra power. How well that DCC waveform fits in with Chris's 12v rail scenario I don't know.

Rob

[Chrissaf]

Actually 6 wires (possibly 7) in total.Two from the wheel pickups as input to the secondary bridge rectifier. Two as output to the motor. Two as input from the decoder. The 7th.....may be required to bond the DC negative of the circuit to the DC negative of the decoder.

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How well that DCC waveform fits in with Chris's 12v rail scenario I don't know.

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Bridge rectification of the DCC to provide 15 v DC perhaps supplemented with a smoothing capacitor. Then perhaps a 12 vdc regulator chip to limit the motor voltage if required. With all that added, then there should be very little of the original DCC waveform left on the 12 volt rail to cause interference.

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[96RAF]

Thanks for the clarification Chris.

[Fishmanoz]

Any DCC waveform left will be low pass filtered out by the highly inductive motor windings, just as it is with normal DCC PWM to the motor, leaving only the average DC value.

[Yelrow]

Gosh, can we get back into simple english. Will they run, as is, yes or no. john

[walkingthedog]

Gosh, can we get back into simple english. Will they run, as is, yes or no. john

Hey John it could be that none of the info above means anything. We could all say oh what a jolly good idea well done just to make it look like we know what it means.  😆

 

Sorry Chrissaf just having a bit of fun, I am in awe of your knowledge of these things. I'm afraid my elecrical expertise on this type of subject left me many years ago. Keep up the good work. 

[Chrissaf]

Your quite right WTD, my original intention was to just let this one pass by without comment. Based on the content having no more than minimal interest to a limited few. However Fishy effectively asked me to comment by name, and I felt it was being rude to ignore him. Had we private messaging on the forum, I think the route I would have taken would be to PM the detail to the interest parties and not publish here. I am totally aware that there are some on this forum (no names, and not you) that are not interested in the technical content of my posts.

[walkingthedog]

I'm interested in some of it chrissaf, but other parts might just as well be written in Slobodian.  😆

[Chrissaf]

I'm fluent in Slobodian....... 😉

[walkingthedog]

I thought you might be, so was Michael Bentine. 

[37lover]

Gosh, can we get back into simple english. Will they run, as is, yes or no. john

I sympathise but previous postings did warn that they might not work, or at least would be at risk of burning out. Chrisaff provided a very helpful possible solution which, if I had any of the older locos, I would be very grateful to see. I can just about understand the waveforms as they pass over my head!

[Fishmanoz]

with a tts decoder ?   no 

 

HFM, the answer isn't no.  The answer is maybe, you'll need to do a stall current test to find out.  In fact someone, I forget who, has reported elsewhere he has an older loco operating with a TTS decoder.  Stall current is mentioned there too.

 

And apologies that the public/private Slobodian conversation between me and Chris, encouraged by Rob, may have confused that.  Stall current is covered earlier though.

[96RAF]

I have old two ringfield motored diesels running on a TTS decoder.

 

Railroad type, probably ex Lima, Hornby Class 90 and Class 56. They only ever run light engine round a small track at reasonable speed so probably never see anything like near stall current as could be reached with a full rake and/or any inclines at full chat on a larger layout.

 

I aim to convert these to DVD motors in the future, but of course a radical motor conversion, even if possible from XO motors to modern can, is not something that a Triang collector would likely want to do.

 

So its all a case of working within limits if you can.

Rob

[96RAF]

Some positive feedback (sorry about the pun) from the technical guys upstairs  about Chris's concept:

 

"The idea is interesting and will work, but has a drawback in that the decoder will not be able to sample BEMF from the motor, thus load compensation will not work, therefore it will be necessary to reset CV10 from = 128 default value to = 1.

Since the motor load is still controlled during service mode programming, then programming and readback (if enabled) will work OK."

 

So well done Chris for a sound design in principle. Any takers to make it.

Rob

[Chrissaf]

The Hornby techs speak fluent Slobodian as well then...........nice to know that the idea has not been shot down in flames and has some merit in it.