DEREK123 Posted July 6, 2016 Share Posted July 6, 2016 HiHow do I know if a magnet needs remagnetising ? .... I am a novice !!Does a slugish motor indicate this ? ... ( mine are mainly X03/4's ) Thanks ... all advice / help welcome . Derek Link to comment Share on other sites More sharing options...
Ruffnut Thorston Posted July 6, 2016 Share Posted July 6, 2016 A slugish motor could be a weak magnet. It could also be caused by a dirty commutator. The brushes leave carbon behind, which can clog the slots in the commutator. The commutator neads to be cleaned every so often. A small pin or CAREFULLY the tip of a craft knife, can be used to clean out the slots, working AWAY from the windings. A dirty commutator can have the effect of bridging the poles of the armature, and you only have 3 to start with! This also applies to car starter motors! I test the magnets by using a screwdriver (steel). There should be a strong attraction, in a good case, you can lift the motor with the screwdriver stuck to the magnet... Link to comment Share on other sites More sharing options...
james_nelmes Posted July 7, 2016 Share Posted July 7, 2016 I would agree with Sarah. The easy test is to use a steel screwdriver which should need some force to remove. I use a free app on my iphone to test magnetic strength called MMF-Meter. In essence as you move the phone near to the magnet you will see the pole of the part of the magnetic you are moving towards and the strength in micro Tesla. The poles are the faces with the hole drilled through. Ideally I like to see at least 800 - 900 but ideally the 'LIMIT' message which shows it is over 1000micro T.I invested in a remagnetizer from e-bay but these are expensive if you only have a couple of engines. You can replace the magnet with a super Neo magnet, again obtained from the internet, but some modellers claim these put too big a strain on the motor. You can also send it off for rewind and searching for "X04 rewind" should bring up a number of people who charge around £15 plus postage. This includes refurbishment of worn parts and a remag. Link to comment Share on other sites More sharing options...
david_poynter Posted July 7, 2016 Share Posted July 7, 2016 I'd concur, magnets should attract a steel screwdriver quite strongly with a noticeable snap.I have remagnetised original magnets and it does make a difference.A weak magnet will also make the motor run hotter.It might be possible to just attach another magnet to the side of the original while it's still mounted in the motor and try running the chassis like that to see if it makes a difference.As others have said, make sure the commutator is clean, especially between the slots as stay carbon can conduct across the gap and reduce the efficiency of the motor or stop it working.Dave. Link to comment Share on other sites More sharing options...
DEREK123 Posted July 10, 2016 Author Share Posted July 10, 2016 Hi and thanks Sarah, James and Dave ...Your help is very much appreciated , Thabks for the replies. .... My Locos are quite old ( like me !! ) and having only dared change brushes in 1 or 2 of them ( I think I should have given the job to a pro as my results are not that good and maybe I was expecting too much ... having said that we all have to start somewhere and gain experience and advice where and whenever possible. )Regarding the magnets they all appear to be good , attracting screwddrivers and many other objects around my bench. Given my level of my abilitiy I don't think that I will go down the route towards test or remagnetising gear although I do have an iphone !! ( nice tip James . )Next job for me will be to caredully clean the commutators.Thanks again. Derek Link to comment Share on other sites More sharing options...
2e0dtoeric Posted July 10, 2016 Share Posted July 10, 2016 When you fit new brushes, they don't always work very well initially.If you look at the surface of the old one, it has worn into a curve. The new one is flat!It takes a little while for a new curve to develop, which increases the contact area between the brush and commutator. Also, perhaps the new brush has not gone in perfectly 'square' so only one edge of the brush is in contact with the commutator.Also check that the springs haven't got strained, so aren't pressing the brush down as firmly as they should.Another cause of sluggish motors, especially in loco's that have been unused for a long time, is the lubricants - or lack of!Over a long time, oils and greases can turn to a form of glue - especially if you habitually used 3 in 1 oil! That's a big No-no! 3 in 1 is penetrating fluid, not an oil, and the carrier evaporates off, leavng a sticky gunge, which collects dirt. So the motor gets sluggish, and you lubricate with 3 in 1, and it gets even more gunged up!Even worse is WD40. It is known to attack and even dissolve some plastics! Link to comment Share on other sites More sharing options...
Michael_A Posted July 12, 2016 Share Posted July 12, 2016 The only scientific way is to measure motor current. For this you wil need an ammeter. Here's an interesting article referring to Dublo magnets on YouTube: Link to comment Share on other sites More sharing options...
BobHughes60 Posted July 17, 2016 Share Posted July 17, 2016 For the price of return postage I would remagnetise them for you if you wish.You can get your email passed via the moderator.Bob Hughes60. Link to comment Share on other sites More sharing options...
DEREK123 Posted August 14, 2016 Author Share Posted August 14, 2016 Hi Bob ( BobHughes60 )Sorry for the late reply , I have been away and just got back .I may well take you up on your very kind offer ... I put my locos in for /examination / service before I went away and have not yet been to "hear the damage" ( estimate !! ) ☹️ ... I will respond as soon as I hear / can.Thanks also to 2e0dtoeric and Michael_A .Thanks again. RegardsDerek Link to comment Share on other sites More sharing options...
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