Throppers Posted June 23, 2020 Share Posted June 23, 2020 HiI have a loco with a 3 pole armature where the windings have turned purple. The motor is down on power even after a full rebuild service. Is the purple colour on the winding a sign that the part needs replacing and will no longer be working efficiently (hence lack of power)Thanks Link to comment Share on other sites More sharing options...
96RAF Posted June 23, 2020 Share Posted June 23, 2020 Purple could be a sign that the windings have overheated but may just be a sign that the armature has been rewound with purple varnish insulated wire. Link to comment Share on other sites More sharing options...
Throppers Posted June 23, 2020 Author Share Posted June 23, 2020 Thanks for the reply. I'm pretty sure the part is all original ie not rewound. If caused by overheating, I'm guessing this would reduce it's efficiency? Link to comment Share on other sites More sharing options...
96RAF Posted June 23, 2020 Share Posted June 23, 2020 If you have a multimeter measure the resistance of each winding by probing from each commutator segment to the next and so on. They should all be the same value. Post back what these values are and someone will tell you if they are OK. Link to comment Share on other sites More sharing options...
Throppers Posted June 23, 2020 Author Share Posted June 23, 2020 So I have 12.9-13 ohms across all three terminals Link to comment Share on other sites More sharing options...
2e0dtoeric Posted June 23, 2020 Share Posted June 23, 2020 You don't state what the motor is.I'm assuming an older frame motor, XO4 or similar. It could be that the magnet has faded, thus causing the motor to be wound up to full power to get any traction, and as a result - has overheated the windings. This will have dried out the oil in the shaft bearings, causing more friction, and causing more power to be drawn!The magnet can be re-magnetized, and if you hunt around you'll find a link to someone who does it (or maybe someone will leap in with their boots on, and give the link). Link to comment Share on other sites More sharing options...
Throppers Posted June 23, 2020 Author Share Posted June 23, 2020 No sorry should have said, the motor is a 3 pole ringfield motor Link to comment Share on other sites More sharing options...
GWR 14xx Tank Posted June 23, 2020 Share Posted June 23, 2020 Things that get very hot do tend to go purple, like soldering irons or hot air guns. I noticed that the end of my soldering iron yesterday had gone purple - most likely due to the extreme heat required to solder, not that it had been rewound with purple wire! 14xx Tank Link to comment Share on other sites More sharing options...
Puffed Out Posted June 23, 2020 Share Posted June 23, 2020 What are the magnets like. If they have lost most of their magnetism, the motor will eventualy burn out. They can be re-magnetised. Link to comment Share on other sites More sharing options...
Simmo009 Posted June 23, 2020 Share Posted June 23, 2020 Scalespeed offer a re-mag and re- wind service. There was a guy called Ronald something who sold a remagnetizer, I think they were around £150 a go. They sometimes come up on a well known auction site. There used to be some videos on YouTube, but I never saw anyone do a ringfield, although they all said it could be done. Maybe worth considering changing to a CD type motor, again videos show this, and there is a chap that does a 3d printed adaptor piece so everything lines up. Link to comment Share on other sites More sharing options...
96RAF Posted June 23, 2020 Share Posted June 23, 2020 If going down the DVD motor route try here https://www.strathpefferjunction.com/hornby-ringfield-motor-upgrade-kits-are-now-available/UK based, no silly prices and what you see is what you get. Link to comment Share on other sites More sharing options...
Puffed Out Posted June 23, 2020 Share Posted June 23, 2020 I bought one of Ron Dodds re-magnetisers, brand new from him. Works brilliantly. It's paid for itself already. 😆 Link to comment Share on other sites More sharing options...
Ruffnut Thorston Posted June 23, 2020 Share Posted June 23, 2020 We have new old stock Ringfield Motor armatures that have purple coloured windings... From memory, there are also reddish colour windings? I'm not able to look at the armatures at the moment! Link to comment Share on other sites More sharing options...
ColinB Posted June 25, 2020 Share Posted June 25, 2020 A lot of my Ringfield motors windings are purple. Those resistance values are about what I measured on my armatures. I have done a lot of work on these lately, one thing to check for is small bits of gravel or dirt stuck in the ringfield wheels, moulded wheels. Go round then with a needle or the like. I could not get one of my motors to push the Duke of Sutherland and it was getting hot (actually burn out my DCC decoder), until I found it. Also check that the brass gear is not "freewheeling" at high speed. The other thing that is very important, or it was on mine, is where the join of the flexible magnet is. I removed mine to drill out the brush locating screw for DCC conversion and couldn't understand why it ran so slow when I rebuilt it, once I got the position of the magnet sorted it ran perfectly. The best way to check is to run the motor backward and forwards using the power supply, it it goes much faster in one direction the magnet is wrongly placed. I don't think ringfields loosing their magnatism is as big an issue as X04s. Link to comment Share on other sites More sharing options...
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