Q: Advice - retrofit NWSL armature into Rivarossi can motors

[mmagliaro]

Speaking of "old school"...
Years ago, you could buy a replacement 5-pole armature for the can motors that were used in the Atlas/Rivarossi steam in the 1960s, 70s, and 80s.  I happen to have one of these with the replacement in it, and the motor definitely runs a lot better than a stock one (slower start and more power).  I happen to have some of the old cans and one of those armatures, new in the package.  Out of curiosity, I though I would put it in and see how it runs.  I figured, "How tough can it be?"  I expected to just swap the armatures, maybe add or remove some thrust washers at either end to get good alignment under the brushes on the commutator, and that would be that.

Well, no.   What I find is that with that armature in the can, there is no way the end cap/brush holder can be pushed completely back into the motor.  The armature is about 1/16" too long, at least.  And even if I could get it back on, the brushes would never line up with the commutator.

Is there some modification or trick to installing these armatures?  I thought they would be drop-in replacements.

[Jim Starbuck]

Max,

It doesn’t answer your question or afford much help but several years ago when I first got back into the hobby I replaced the stock three pole armatures with five polers in a few Atlas/Rivarossi steamers and I think a C-Liner that had been given to me by an old school friend just to resurrect it.
They came from a seller in Pennsylvania and other than having to trim the shafts to length, they went right in.
They do run much smoother than stock.
Was there more than one size of the old can motors? Perhaps a long and short version? Seems like the C-Liners and E-8s may have been shorter because they were mounted vertically but my memory might not be working at full capacity.
There might be some information on the A1G site.

http://www.irwinsjournal.com/a1g/a1glocos/

Jim

Edit:
Looking at the A1G site and it appears there was only one size motor for the various engines.

[C855B]

Don't forget that one of the (many) problems with the RR motors was the plasticized magnets, weak in the first place, would sometimes lose their magnetism altogether.

[Doug G.]

The cans were all the same length. The bushings can be repositioned as they will move in the plastic cap and lower housing but I don't know if it would be enough or if the commutator would line up satisfactorily with the brush holder openings in the cap.

It's kind of weird. If that armature is one of the ones that was supposed to be a drop-in replacement, you wouldn't think you would have to tinker to get it to work. Actually, I may be thinking of the ones offered by the Motorman - Eldon. I'm not sure I knew of NWSL offering them.

Doug

[peteski]

Back in early 2015 I bought some 5-pole armatures for Rivarossi motors (or was it the entire motors?) on eBay. These armatures were smaller diameter than the stock 3-pole ones, and were also shorter. They also seemed to have fewer wire turns wound on them.  They ran smoothly, but because of the larger air gap, they had very little torque.

At that time I exchanged few PMs with @rodsup9000 about those. He was also planning on upgrading his motors.  I think he mentioned that his friend Gene was making those armatures.  Maybe Rod can chime in here and provide some more info?  I never really got anywhere with that project ( I was thinking of replacing the magnet), but those armatures are sill hanging somewhere around my workshop.

[u18b]

Max,
I only tried something like this once.  And it was not entirely successful.

I had a burned out motor to a brass KMT B&O E set.

I found the guts to a Bachmann DASH-8 was the same size -- AND it was 5 pole skew wound.  So I opened up both motors and pulled the poles/commutator assembly.

The Bachmann was a non-issue since I was destroying the motor....

But the KMT was a bit tougher.   In order to get the plastic brush housing out, I had to bend the frame apart a bit.  The new guts went in perfectly.
However, the frame was not exactly as it should have been- and the motor was not perfect.

The loco ran great for a while and I was proud of myself, but it died some time later.
It's still sitting in a drawer waiting for a new motor.

So..... my experience is that success depends on if you can keep your motor frame as perfect as possible when receiving the new guts.
And those can motors might work great.
My open frame experience was not so great.

[mmagliaro]

Well, this conglometation of confusion is about where I landed on the whole thing.  No, the end cap bearing and metal can bearing cannot be pushed in enough to accomodate the NWSL arm.  I tried. 

In any event, it's time to reveal more about what I'm working on.  I have had some special neodymium ring-shaped magnets manufactured to exactly fit into the RR cans.  My plan was to find some bulk motors with the correct size armature that would drop in to the RR can, along with real magnets to replace the rubber piece of junk that is in there, and have a sort of "super upgrade" kit for these things.

I'll start a separate thread on this, to keep it organized.

I know they are old-school engines.  But I think a lot of people still have them, many with dead melted motors, and would love to put them back on the track again if only there was a simple screw-in replacement motor that didn't require frame grinding and scratch-kit-bash-nerding to get in there.

I found some 3-pole motors with heavy skew windings that look a lot like the one used in the LL 0-8-0, which was an excellent running motor.  I'm trying to get those to fit into the cans now.

[peteski]

I found those 5-pole Rivarossi motors I bought on eBay few years back. I figured that I would post some photos here for reference  Since these armatures fit the motor (and  need washers to reduce the play in the shaft), they are not NWSL armatures.



This photo compares the 5-pole to the original 3-pole armature. The 5-pole one is much shorter.



Here you can see the large air gap between the poles and the magnet, and how sparse the winding are.  All of this results in very weak torque,

[mmagliaro]

Yeah, you don't want a big air gap like that.  You get lower torque and more speed --- the last thing we want in a model train motor.  But those RR rubber magnet liners had problems with swelling up or having "thick spots", so maybe they were thinking a smaller arm would allow for more slop in there.
My hope is that my replacement magnets and armatures are going to fit "really close". 

[nickelplate759]

Speaking of "old school"...
Years ago, you could buy a replacement 5-pole armature for the can motors that were used in the Atlas/Rivarossi steam in the 1960s, 70s, and 80s.  I happen to have one of these with the replacement in it, and the motor definitely runs a lot better than a stock one (slower start and more power).  I happen to have some of the old cans and one of those armatures, new in the package.  Out of curiosity, I though I would put it in and see how it runs.  I figured, "How tough can it be?"  I expected to just swap the armatures, maybe add or remove some thrust washers at either end to get good alignment under the brushes on the commutator, and that would be that.

Well, no.   What I find is that with that armature in the can, there is no way the end cap/brush holder can be pushed completely back into the motor.  The armature is about 1/16" too long, at least.  And even if I could get it back on, the brushes would never line up with the commutator.

Is there some modification or trick to installing these armatures?  I thought they would be drop-in replacements.

Going through my NWSL parts box today I found one of these armatures sold as useable for retrofitting a Rivarossi motor.  NWSL part 10052-9 "9.5 x 13mm 5 pole skewed armature". Says it's really for a 14x20mm Sagami motor but can be used in a Rivarossi as well with some fiddle.  Has instructions and extra  washers.   I've had it more than 30 years.

[mmagliaro]

George,
Yes, that's the one (the NWSL part).  I do not see how it could ever work without modifying the can.  From my experiments with new magnets and armatures, one thing I have realized you can do is press the bearing out of the metal can end, and then press it in from the OUTSIDE instead.  That can get you about .030" more space at that end.  I don't know if it's enough to accomodate the NWSL arm.  I didn't try it.

By the way, my project with retrofitting a new armature and magnet into the can is going well.  I have all the pieces and
have been experimenting.  The magnets are amazing.   Those old RR rubberized things can barely pick up a steel nail.  When I hold one of these neodymium ring magnets near anything metal, man, hold on to your hat and get out of the way!

I have a few very good-running examples.  I will unleash details on the unsuspecting public (Railwire)
soon, after I run a couple of them in a Rivarossi engine and see how they do.   A skew-wound 5-pole armature that can actually fit that can properly would have been ideal, but there ain't no such beast.  So I went with a 3-pole skew-wound.