Re magnetising

[barney121e]

Hi All

 

Just wondering if anyone can tell me what difference they noticed with their loco when they got the magnet in the motor re magnetised.

 

Cheers

 

[SR71]

Vintage stuff from the 60's and earlier you will see benefits but metallurgy since then improved such that I've rarely to never seen anything in need.

[JWRStation]

You will find that the motor requires a higher voltage to start and run resulting in a lower speed for the same speed controller setting (when on Analogue) BUT, it will be more efficient and run with a lower current.  The difference will depend upon how much of an increase in magnetism has been achieved; if it is only a small amount then it may not be particularly noticeable though generally even a small amount can give smoother starting and slow speed if the original magnets had well lost it.

 

Joe 

 

[Pebbles]

K's original motors - that is those with two magnets - had 5 poles, to a small degree this addressed the cogging issue, but not entirely. Many years ago, at the Nottingham show, the late Mike Sharman showed me a motor using the K's armature and magnets married to machined pole pieces of the same width as the originals but with a very small airgap. Apparently the result was rubbish, it failed to start smoothly and displayed excessive cogging.

Fast forward to some time later. There was a small outfit on the south coast who produced replacement motors for Hornby Dublo Ring Field motors. These would use either the MRRC armature or Margate Hornby three pole armatures. Now the magic! the inner radius of the pole pieces was 30% greater than the radius of the armature but with a very small airgap. I have tried this and it works, although making the pole pieces was a bit of a bind.

OK, where the magnet has lost its magnetism possibly re-magnification will help. However, often the motor will be so old that the bearings will be worn and all that restoring the magnetism will do is produce excessive cogging and, as been mentioned, require a higher starting current resulting in jack rabbit starts.

Finally, the rear bearing on an XO3/4 is rather flimsy and more of a stabiliser, the front bearing being the main one. Packing the rear bearing with grease can help, but once worn it really needs replacing.

 

 

 

[DCB]

I think an in situ Remag is the only cure for the K's Mk 2 etc which are glued together and can't be reassembled to stay together by folk like me.   I usually nock the armatures for H/D Wrenn 1/2" motors, they also fit X04s when shortened or Triang Power bogies.  They fit both though X04 don't  work in power bogies or vice versa.

I have had 3 poles run ridiculously slowly around 60 rpm, on 60:1 gearing, which is 1 rpm of the wheels which is absolutely pointless 60mm per rev, 3600mm per hour 1 ft in 5 minutes.   But that was a Hornby Dublo ring field with adjustable end float set up carefully.  X04 as  supplied doesn't have any way to tune out the end float, the armature shuttles fore and aft and the drive axle moves sideways and with everything floating about smooth starts become challenging.  a ball bearing between armature shaft and magnet and another bearing on the worm end of the armature with the axle sideplay reduced to around 10 thou will improve starting.  

A remag may help but if the bearings are worn may make things worse, the proprietary  Super neo conversions seem much too strong so I use a stack of chinese cylindrical super neos with iron packing to replicate the strength of the original magnets.  They also let you shorten the X04 magnet space quite a bit which is handy when you have the motor filling the cab as on 4F  2p etc.