Raven_Electric

Hi Tradman I was delighted to read your post because I encouraged yelrow to go for it on his Hornby Dublo 3 rail DCC project. It will be a lot of work for him and to justify that it needs to be a pretty impressive success. If you read back Fishmanoz identified power demands from these old locos as a potential problem and he specifically drew attention to the tired out old magnets so your experience has confirmed his fears. A 40%+ drop in power demand to 300mA is startling, it just goes to show how important attention to detail is in these projects. Keep your eye on this thead because I sure when he sees your post you will be hearing from yelrow. And, I expect the cry will go out how does one get magnets out to darkest France!

I am sorry, timed digital control of power supplies to ANY apparatus has absolutely nothing to do with a current being "drawn" by a potential difference across a circuit. Equally, because of designed in redundancy a locked stationary motor would be capable of considerably more torque and thus current "draw" than would be needed to commence rotation in even peak load conditions so, without the design spec, or output performance testing to create it, the information obtained when stopped is of indeterminate accuracy or value for anything. A more useful piece of information would be just how many milliseconds it would take to commence destroying windings insulation on those eighty years old motors by subjecting them to what is in effect an unlimited current system short and this is NOT an either or situation, excessive heat for only a very short time can cause a progressive insulation breakdown to commence as air gets into cracks AND this, depending on insulation type, may continue after the excess heat is removed. I ask myself, would I learn something of use to me about an 1100 volt traction motor by risking destroying it (and those around it) through bolting up the shaft and hooking it up to a power station? I think not. I can assure you, this is not how things are done in all the best circles. Many great minds have, over many years, devoted a lot of ingenuity to devising some really interesting pieces of equipment (especially for coal mines) that exist only to prevent the very circumstances you seek to encourage! There is a fine 190 year tradition that if the train doesn't go fast enough stuff something bigger in and that works equally well with boilers and decoders! As far as operating on the brink of disaster goes I have been too close to too many big heavy things going very fast for too many years to consider doing that. I threw the old envelopes out and built a computer for the calculations forty years ago for that very reason. I mentioned before the R8249 is in play because I recall yelrow saying he had one. There are no profiling facilities but it is small so easier to install and more than compensates for its low spec with its size. low price AND very reliable current sensing (I have a few and I've tested them all a few times with 100% success). Your XO4 motor would have been in safe hands running on the R8249 because the cut out is set at 1amp. I have suggested to yelrow that an R8245 be obtained for diagnostics. He may find that with profiles and other whizz bangs setup that, at least for his top link shed, he can spare the extra cash to get hold of the extra fun! From my point of view and interest the R8245 is just dandy as Hornby's coup do grace has been to push the boat right out and support Lenz's RailCom so those diagnostics will flow straight off the tracks into my spreadsheets - that is what I call testing.. Frankly other than simple guidance on which bit to solder to which bit and what to check for continuity and insulation I think yelrow's biggest problem on this project isn't technology it is sanity. There must be a limit on just how much soldering a man stuck in darkest France can actually cope with before the men in white jackets arrive to cart him off. What is needed on this thread while the soldering continues is encouragement. Anecdotes on just how good a loft full of die cast trains flying around really are as they decapitate all in sight when they come off on the bends! Memories of badly cut fingers from tin plate carriage ends and Dinky cars with no tyres welding themselves to the level crossings. We've given all that up for "finescale" and sixteen engines all crashing into each other like rats in a sack. I made it to the loft this evening and have returned with one of those beautiful Hornby die cast grey controllers with the lovely long chunky chrome throttle lever. THAT IS the business! What railways are all about. I think I will have the guts out of a Select and put my top shed local controller where it should always have been in a beautifully finished, chrome topped die cast box.

Hi Fishmanoz I recall yelrow saying he had an R8249 which is why I suggested it as a handy, good value, reliable starting place. I had a pleasant day on the North Yorks Railway a while back being pulled by Sir Nigel at 25mph max. I'm not suggesting that such a scale speed should be the limit of yelrow's ambitions but he is after all running a Heritage Railway and in my view some respect needs to be shown to these venerable old beasts! (I include myself on both counts). I never had a Hornby Dublo three rail layout so I don't really know why I have bits and bobs of stuff (which I am sure I do) but I do remember a couple of pal's stock flying round at about a scale 250mph with a few carriages barely hanging on the track behind them. After hours of this they weren't glowing red and (unlike my own) didn't smell like spontaneous combustion was imminent so the motor/mechanism cannot be that inefficient. I would be very happy with a scale acceleration to a max of 70 mph for my mainline "Heritage" stock and in OO I would consider that something was wrong if I could not get that from a digitally poked 10watts and R8249s deliver that for me without complaint. However, I defer to your greater knowledge and if yelrow needs more speed then the R8249 can be swapped out for something more beefy before he buys more as he is wisely fitting sockets. I have a little experience of very much larger and a great deal more than considerably more expensive motors than are found in model railways of any scale. Anything can be re-wound or mended, even improved with better and closer tolerance bearings etc. The point is at what cost and would it be worthwhile? I don't consider putting a relatively high dc current through an artificially seized motor to be any kind of "Test" whatsoever more of a high risk gamble with a possibly perfectly satisfactory winding to find out something I don't need to know. How fast yelrow's locos could go or what their maximum trainload may be is not important. What matters is that they go fast enough and pull enough to deliver his timetable with a little bit more reliability than Sir Nigel's finest ever managed. If they do then Job Done as Sir Nigel never got to say. Just one of the joys of DCC is that locos can be profiled not only to help protect the motor but also to enable very accurate calculations of just what can be done and at what speed with a fair stab at quantifying the associated risks.

I call the power collector the two sprung spoons underneath that run along the third rail. If I remember it usually sat on a bit of brown circuit board but I'm blowed if I can remember if it was screwed or rivited on. Screws would be best for checking the wiring etc. No I don't have an eLink. I've got some expensive German and American stuff but I prefer the the Elite which of course can use Railmaster though I usually use either JMRI or software I wrote myself. The latter usually for reading/writing CVs as it flows straight into/from my spreadsheet entries where I keep/tweak my various decoder CV settings and performance curves etc and I write/read ALL bits of CVs memory by way of error checking first (some very expensive decoders have had dodgy static ram). My prog is compiled so runs much faster than JMRI which is written in interpreted Java but I still don't sit around waiting while it runs! I have tried Railmaster for reading writing CVs without problem although of course it can't be automated (as far as I've looked) so there will be no difficulty there when you get to that stage. If yu've found an electronic store in France don't forget some 2mm and a bit bigger (works as cable ties too) heatshrink. At least a couple of metres of both. I am sure Premier Farnell will deliver first thing next day anywhere in France and lots of the eBay traders will too. Your other issue later will be beefing up continuity on your rails and points so get a little solder at different temperatures and a pot of flux and some wire wool (Baker's Fluid was the stuff but Health and Safety saw that off) and play around a bit. If you've got loads of track sitting around soldering tails onto a few lengths would be handy. It is up to you how you deal with points. DCC wants the whole thing live but you may wish to be able to continue to drop power to unused roads. You could solder on long enough wire to chop the wires later and rejoin or safely terminate in chocolate block I suppose. (Better get some 3mm and 4mm chocolate block too) If you are not up to much soldering now hold on doing the chip harnesses because you will be solderer of the year after a few rails.

The R8249 can propel a current Hornby range R2339 Mallard hauling 10 Gresley R417x series 61'6" coaches at a scale 92 mph in level running and well exceed scale acceleration with train lighting on. I accept 10 tinplate carriages with bearings of unknown resistance will likely offer a MUCH greater load. However, the R8249 is rated at 500Ma continuous with a 1Amp peak. From what I remember of those motors I would be very loathe indeed to put more than 15Watts through nearly eighty year old varnish insulation, (at first anyway) once it is gone it is GONE. The R8245 offers 1.5Amp and unless a boiler is going in for train heating that would worry me at my age let alone nearly eighty! In any event I suggest an R8245 for diagnostics and it will easy to swap the R8249 to newly prepared locos for testing because NEM sockest are being fitted and the choice of decoder for the whole fleet can be deternmined after tests.

Well here we are on a 3 rail model railway thread. My goodness isn't life interesting. To recap: 1. One set of leads come from the "Programming" output of your controller. ONLY EVER use these to connect a special programming track for one decoder equiped item at a time. You CAN use a two pole three way switch so locos can run onto the track when it is in "Main" mode and tben be programmed when you throw the switch to "Programme" mode. Throw the switch back again and the loco can leave. There are very good but long and tedious reasons why this is best practice. 2. The leads from the "Main" output of your controller can run one track system or be split to run more than one such aa a two rail layout and a 3 rail layout. There is no theoretical or practical objection to this indeed block isolation is not exactly new in railways. 3. You really must obtain NEM 652 wire harnesses. Soldering wires from decoders without an expensive anti-static soldering setup is not recommended for your wallet. 4. You need to strip, clean and service each loco. If the collector mount (possibly brittle with age) is screwed on then remove it and check the condition of the wire going up to the motor. DCC puts far more demands on insulation than dc operation. The 15vac is constant whereas dc systems rarely get anywhere near 12 volts. 5. Because you will be cutting ends off the NEM 652 harnesses you will have lots of colour coded suitable wire to replace wire where a. the insultion is hard and brittle b. the termination is loose or of poor quality c the colour coding is confusing. It is good pratice to use the NMRA DCC colour coding (below) thoughout your fleet. 6. You also need some 2mm od heat shrink to hand in case you need to join wires. 7. Solder the ORANGE wire of your NEM connector to the motor terminal the collector was soldered to. 7. Solder the RED NEM connector to the collector wire or terminal. 8. Disconnct the other motor connector wire and solder the GREY NEM connector wire to the motor terminal. 9. Solder the Black NEM connector to the wheel pickup wire. 10. Plug in a Hornby R8249 decoder (Avoid static) 11. Ensure NO wires can rub or vibrate and damage their insulation. 12. Ensure the R8249 decoder cannot touch anything or short and has free air all round it. 13. Box up and place on a 3 rail programming track and write CV1 address 14. Play trains NEVER use heatshrink on decoders. It is hydrooarbon derived and has a high calorific capacity, very poor thermal tranfer and seriously impairs air circulation round the the ICs and board. Power chips in decoders are highly stressed they MUST have adequeate cooling. NEVER lift a DCC equiped loco on or off the track while it is selected (or already in running mode} by the controller. contr Be aware insulation on very old motor windings can be in a state of terminal breakdown. This CAN be tested but usually puts them beyond repair. In this state they may work extremely slowly in dc (for a while) because of the low voltage. They are likley to fail in DCC or trip the power supply cutoff. In any event once the loco is working both back EMF response nnd power curves need setting. This should be done with the age of the motor in mind. The Hornby R8245 Sapphire chip contains further diagnostic CVs and at least one should be obtained even if not need for functionality to be used to produce diagnostic reports on the state of the fleet's motors - this could prevent failure. Details on an auto 2/3 rail switch track and decoder installation for use with modern locos to run on three rail will follow later. You need to acquire some power collectors.