Observation of old Bachmann locos.Bad Magnets..

[LV LOU]

    I posted a thread on older Bachmann C40's a week ago,on trying to get them to run.I had some success totally cleaning them out of all grease and lube,and other mods.I took apart all I had,over a dozen,all run at least half decent now,but still not as good as they should.The one thing I did notice,however,is what I believe is the root of the problem.The motor magnets are DEAD.They have virtually nothing left,which is why the lube was so critical.I'm going to see if I can devise a way to "ZAP" them..Sooner or later,these locomotives will completely grind to a halt,since I believe the magnets are at the end of their life.

[peteski]

Are those the dark-colored ferrite/ceramic magnets ( http://en.wikipedia.org/wiki/Ferrite_%28magnet%29 ) or are they made of metal (silver)?  In my experience the ferrite magnets don't lose their magnetization. I'm not sure if you'll be able to "zap" them like it can be done to the metal-based magnets.

[LV LOU]

 Ferite..I'm sitting on my patio right now,with a set of magnets fro a hard drive,and a compass.They can be remagnetzed,although they never really get super strong again.I had a real magnet zapper for RC car magnets years ago,but sold it to a hobby shop.I actually have a need for one to zap motorcycle magneto magnets,I may build one.If I do,I can zap the motors in these things for you guys..

[kalbert]

All my really old locos have incredibly weak magnets in the motors, but my assumption has always been that they were just crummy motors and the magnets have always been wimpy and never ran well. It seems like they used to run better than they do now, but I think I'm just spoiled by how good newer motors run and forgotten how bad the old stuff actually was.

[LV LOU]

Well,the "zapping" with the rare earth magnets actually helped!!I use two nasty magnets from a computer hard drive.I may try a set of HO racecar magnets I have.
  Get a compass.Put either the top or bottom of the motor near the compass.[On a Bachmann -8,the top is north..] Mark that end with an "N".Now,get your magnets..Do the same thing,until you find one flat side that registers north,one south.Mark the OPPOSITE side of the magnet with the appropriate pole.Now,simply place the magnets,markings out,on the appropriate side of the motor can,and rotate the magnet around until it sits as well as possible over the motor magnet,close to the center of the rare earth magnet as possible..Haven't had time to see just how good they'll get say,overnight,but at the moment,with the rare earth mags removed,the motor will at least stop suddenly on a segment and snap back when you spin it,before it did nothing,just rolled to a stop wherever..I do have the brushes out..

[mmagliaro]

Well, I don't know if these count as "really old", but I have Sagamis from the 90s, and
Life-Like open-frame motors from the 90s, whose magnets are certainly not weak.  So I don't think it's
normal for a motor to have weak magnets.  I expect them to be strong enough to make it a pain
to put the armature back in the housing, because the magnets keep trying to pull the armature to one side (if one is
so inclined as to remove it, that is).
When one of those old LL motors has a magnet that has come unglued from the frame, sometimes
I don't notice it right away because the magnet keeps itself so firmly attached to the frame.

Oh, whoops, what I meant was if those magnets are that weak, then they are probably NOT like they were
when they were new.

[LV LOU]

Max,these things are so weak,if you take out the brushes,and spin the arm pretty good,it'll spin for 4-5 seconds.Now,that is with pretty big flywheels on them,but I'm only spinning them with my fingers.You can slowly turn it,and stop it wherever you want,no camming whatsoever.They actually did start camming AFTER I zapped them..I have two extra motors.I think I'm gonna try an experiment.I have a smal battery Dremel that runs at a very constant speed.I made a driveshaft that fits in it,a regular Bachmann shaft with one end cut off. I made it to check the trucks,and run the motors in cleaning solution.I'm gonna do tests on these motors to see just what they gain by zapping.I'll put a load on it across the brushes,any old resistor,run it,and do a voltage check,running it as a generator.I'll do it before zapping,after an hour,,two hours,three,after a day,2 days,ETC,and see how long it takes to get maximum benefit,if any at all...

[kalbert]

Well you've got my attention, curious to see what you find out! Sounds like the basis for a science fair project!

[Lemosteam]

Why not just replace the mags with rare earth mags?

[LV LOU]

John,any magnets would be better,but where would you get an exact size magnet? The Bachmann motors are a PITA to take apart,not even worth that kind of work.I'm certainly not gonna go through all that for marginal locos to begin with.Just slapping a set of magnets on the can is about as far as I'm willing to go,even that almost rates as "extraordinary measures" for these things.I'd just replace the motors,but I have 13 of them,and their shipping is murder..

[peteski]

I'd just replace the motors,but I have 13 of them,and their shipping is murder..

Wouldn't the shipping cost for 13 motors be the same (or just slightly higher) than for 1 motor?  I've ordered parts from Bachmann lots of times and I don't recall the shipping charges as being exceptionally high.

[LV LOU]

Yes,but 12 or more motors plus 10 bucks or more shipping = WAY more than I'm gonna spend on 12+ junk locomotives.....