Daltons IT Posted March 14, 2015 Share Posted March 14, 2015 I'm a beginner with dcc and have some trouble to convert an old class 35 with ringfield motor. I read about stall current too high. How to measure it? I am Italian but love so much British railway models.thank to anybody to help me Link to comment Share on other sites More sharing options...
poliss Posted March 14, 2015 Share Posted March 14, 2015 It's explained on Brian Lambert's website. http://www.brian-lambert.co.uk/DCC.html#NORMALWith my multimeter I have the dial switch pointing to 10A and the leads , one in the common and the other in the 10A socket as most motors stall at half an amp on n gauge and 1 Amp on 00. If you're having trouble, it could mean that the commutator brushes are worn or a damaged armature. Link to comment Share on other sites More sharing options...
Daltons IT Posted March 15, 2015 Author Share Posted March 15, 2015 Thanks a lot PolissI'll follow your suggestiob and I will read Brian Lambert web site. I have already burned 1 decoder R8249 trying to concert this loco and I would like to avoid burning another one. I will post the results Link to comment Share on other sites More sharing options...
96RAF Posted March 15, 2015 Share Posted March 15, 2015 It may not be a stall current problem but a ringfield conversion problem that is burnig your decoder D-IT.There are several different ringfield motor variants and they all have special methods to convert them to DCC.Which model is it (R number) and can you post a picture of the motor. Is your model R2410 or R2423 as shown on Hornby service sheet HSS272 which can be downloaded from this site.Brian Lamberts site also covers ringfield conversions. Link to comment Share on other sites More sharing options...
Daltons IT Posted March 15, 2015 Author Share Posted March 15, 2015 Thanks RAF96, The class 35 hymek is the one shown on the service sheet 93 & 93aI will give you more details tomorrow, I am currently not at home. Link to comment Share on other sites More sharing options...
Daltons IT Posted March 15, 2015 Author Share Posted March 15, 2015 Loco is a class 35 (type 3), model is R.074, no D7097, service sheet 93A. Powered bogie service sheet 106.hope these info would help to understand which is the ringfield motor. Link to comment Share on other sites More sharing options...
Fishmanoz Posted March 15, 2015 Share Posted March 15, 2015 A check of service sheet 93A shows wired connection to only the right hand brush connector of the motor, meaning the left must be connected to chassis via the metal screw holding the connector in place. The screw must be replaced with a plastic one to isolate the connection from the chassis as per the Brian Lambert instructions for this Ringfeld type before fitting a decoder. Failure to do so results in instant decoder destruction, as you have already found. Most people report an 8249 then has sufficient power for this motor, although a higher current type gives you a little insurance if the magnets are weak such that the motor draws more current. Link to comment Share on other sites More sharing options...
Daltons IT Posted March 16, 2015 Author Share Posted March 16, 2015 A check of service sheet 93A shows wired connection to only the right hand brush connector of the motor, meaning the left must be connected to chassis via the metal screw holding the connector in place. The screw must be replaced with a plastic one to isolate the connection from the chassis as per the Brian Lambert instructions for this Ringfeld type before fitting a decoder. Failure to do so results in instant decoder destruction, as you have already found. Most people report an 8249 then has sufficient power for this motor, although a higher current type gives you a little insurance if the magnets are weak such that the motor draws more current.Hi Fishmanoz, many thanks for your reply. I'll check more carefully the wiring to be sure that the two brushes are perfectly insulated. I'll post the result as soon as I have succesfully done the conversion (if I will succeed) Link to comment Share on other sites More sharing options...
The son of Triangman Posted March 16, 2015 Share Posted March 16, 2015 One vital thing forgotten is that if the motor is early as in sheet 93A then the brush contacts are fixed onto the faceplate and not screwed on and the motor contact that has the link wire on that runs to the chassis casting has a cast pin under under as belt and braces. This contact needs to insulated or you will blow decoder after decoder. Sheet 106 clearly shows the metal cast pin on the left of the casting. Link to comment Share on other sites More sharing options...
Daltons IT Posted March 16, 2015 Author Share Posted March 16, 2015 One vital thing forgotten is that if the motor is early as in sheet 93A then the brush contacts are fixed onto the faceplate and not screwed on and the motor contact that has the link wire on that runs to the chassis casting has a cast pin under under as belt and braces. This contact needs to insulated or you will blow decoder after decoder. Sheet 106 clearly shows the metal cast pin on the left of the casting.I have finally carefully checked the motor and the wiring are ok, but I discovered that the spur gear installed on the armature axle isn't firm. Sometime it rotates and sometime no. This probably causes the fluctuation of the current that I observed, with peaks that exceeds for a while 2 or 3 amp. Do you think this fluctuation could really be due to the spur gear issue? Since I haven't a spare spur gear I was wondering to try to fix it with a drop of loctite glue. Would it be a solution?thanks a lot. Link to comment Share on other sites More sharing options...
The son of Triangman Posted March 17, 2015 Share Posted March 17, 2015 High current drain is usually down to coils on the way out, intermitant short or weak magnets, a weak magnet is the usual cause. The gear won't help the situation and is best replaced with an S.2290 brass gear as the later mazak gears(shiny grey/silver) metal used are prone to cracking and swelling due to impurities in the metal. Link to comment Share on other sites More sharing options...
Daltons IT Posted March 17, 2015 Author Share Posted March 17, 2015 High current drain is usually down to coils on the way out, intermitant short or weak magnets, a weak magnet is the usual cause. The gear won't help the situation and is best replaced with an S.2290 brass gear as the later mazak gears(shiny grey/silver) metal used are prone to cracking and swelling due to impurities in the metal.If the cause is a weak magnet, do you suggest to replace the complete motor? Link to comment Share on other sites More sharing options...
Blackbird Posted March 24, 2015 Share Posted March 24, 2015 Hi, Your question was; How to measure stall current, You have been given many explanations as to how high currents occur, and how to reduce them. But to measure?Basically you need an Ammeter, or a mutimeter that can measure current, connected in series with the feed to the track. This is with a DC supply. With the Loco under test on the track, apply full controller power, but hold the loco stationary, stalled, and read current. This is the stall current. Link to comment Share on other sites More sharing options...
The son of Triangman Posted March 24, 2015 Share Posted March 24, 2015 Blackbird has it spot on about measuring stall current. I will say that when measuring stall current the loco should be stalled for a few seconds only or the motor coils will burn out.If the magnet is weak then it can be remagnetised and there are places that do this for people for a fee. Link to comment Share on other sites More sharing options...
Flashbang Posted March 24, 2015 Share Posted March 24, 2015 I thought all this was explained way back in post 2 by Poliss, who also provided a link showing how to undertake the testing! Link to comment Share on other sites More sharing options...
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