Rivarossi Revival - Repowering Old Steam with New Motors

[randgust]

We can disagree on fine points but you agree on my key one, you just have to get a motor and try it.   And that's OK in the era of Ebay and Amazon where some of the darndest things show up for reasonable prices with little technical information.  If you think too hard analysis paralysis can set in.   

That philosophy of mine is why I have drawers and drawers of parts and most of my opinions are based on my own experimentation, much of which has has failed but the winners are amazing.   Every time I see another new mechanism out there I've got the overwhelming urge to get one to test and tear apart.   One of my all-time favorites was Chris333's conversion of the Atlas 2-6-0 to Faulhaber tender drive, wow, was that a landmark.

I got a run of cheap 6mm 9V motorola pager motors several years ago with high hopes of powering my GE 25-tonner with those, epic fail on the torque side.  Got one of those gearhead Mashimas from Gizmoszone when Max was tinkering, it's in the parts drawer for surprisingly high vibration noise.    Ya just got to take a shot at it and not get completely frustrated if an idea doesn't work.

Back in the 1880's the level of experimentation on real steam was in full swing, you have to admire this guy for trying:
http://www.douglas-self.com/MUSEUM/LOCOLOCO/fontaine/fontaine.htm
My hero, misguided and all - I'll prove it won't work!
 

[Mark5]

Back in the 1880's the level of experimentation on real steam was in full swing, you have to admire this guy for trying:
http://www.douglas-self.com/MUSEUM/LOCOLOCO/fontaine/fontaine.htm
My hero, misguided and all - I'll prove it won't work!

Oh wow, splitting my sides on this one!  It looks hilarious, but to me it's even more funny that the guy somehow convinced them to actually build these prototypes.

Mark

[JMaurer1]

Having several of the old Rivarossi engines (I started in N some 35 years ago...seems like only a few years) that I detailed for the SP, and even though much better running Pacifics and Mikados have come out, I watch your experimentation with bated breath. I really would like to make them run better, so I watch with fingers crossed.

[mmagliaro]

Okay so one of my Retro Bros on the face toobs recommends this motor as an almost direct swap.
https://www.ebay.com/itm/DC-6V-12V-27000RPM-High-Speed-Mini-DC-Motor-DIY-RC-Slot-Car-Drone-Toy-Model-/192873670885?hash=item2ce82aa8e5&fbclid=IwAR1jXmt4DKtxc1WfI_EQ2-XWZ2ECnVmfBN2V52ZXH01kd6guWWQnyJBVQb0

12v rated, 2mm shaft, so definitely less fiddling to do with it, but open frame, skew wound... looks a lot like the later motors that Rivarossi used during the Con Cor era.

Any thoughts?  They're certainly cheap enough.  I might order a couple for the next batch of projects.  (I might have all of the current batch done by the time the slow boat gets here from China...

Lee

Lee,
That eBay motor has a 1.5mm shaft, not 2mm, so it's much closer to what you need than you think.

And in fact, it is the VERY MOTOR that I am using for my Rivarossi motor retrofit project.

Some of you may remember I talked about this a few months ago.  It has not been abandoned.  I have successfully
transplanted the armature from that motor Lee is showing into a Rivarossi can, with a new Neodymium magnet ring
to replace that awful rubber magnet thingy.  It works really well, definitely better than the original.  It still can't make
a Rivarossi "creep", but I think with the 15:1 gears and the axle tender pickup, that's not going to happen without
a serious gear reduction.  It can do a solid, smooth 15 mph, it draws 1/2 the current of the original, and best of all, it will never smoke or melt even under a full stall like the RR motors do.  My goal was to "convert" the RR can so that it could just be dropped back into any RR steam loco.

That eBay motor still has a 3-pole armature, but it is skew wound, and the armature, commutator, and brushes and brush springs
are far more robust than what's in the RR motor, so the end product after transplanting those parts is much improved.

I'm still working on it.  Sorry it's not ready soon enough to save Lee's engine.

As for putting the whole motor into the RR engine just as it is on eBay, I'm sure you could manage it, but it will require frame cutting
and reaming. The metal case of that motor will not fit into the RR cavity.

[mmagliaro]

Randy, you have that backwards.  For permanent-magnet electric brushed DC motors the maximum torque is at stall (not at peak RPMs).  When the motor is stalled, there is no BEMF being generated, so the maximum current flows through the winding, creasing maximum magnetic field (thus maximum torque).

I have those 6-pole motors Max recommend to Lee. Actually I found those on eBay and pointed Max towards them. He got some and was very impressed by their torque.  While I don't have any measured results, I can tell you that for what they are (standard motors with iron-core rotor), then have very impressive torque.  My test is my calibrated fingers pinching the spinning shaft.     They really are impressive.

That's how I "tested" my Minebea motors too.  When a motor starts turning at 0.5v, slow enough that you can see the shaft turning and count the revs, and by 1 volt, you can't stop it with your fingers, that's enough for me to say "wow".   Other basics: A full stall at 6 volts didn't appreciably heat up a Minebea motor, a good attribute for a model train motor because when things go wrong, motors get stalled, and we don't want it to "cook" if that happens.  I was even able to fully disassembly the Minebea and press the shaft through the armature a little to convert it to a dual-shaft version ( don't get too excited... it was very tedious and a LOT of work ).  The only thing I don't know about the Minebea motor is how long it would hold up under load in every day use on a model railroad.  Would the brushes just wear off after 20-30 hours of use?  I don't really know.  But they are those delicate metal finger brushes, not spring-loaded beefy carbon brushes like you see in a Kato/Atlas motor.

The thing I likes about transplanting the armature out of the eBay motor Lee linked to is that it has bigger brushes and brush springs than the RR motors, so if you transplant them, they can handle the current even on a full stall.  The RR springs and brushes self-destruct under those conditions.  That is the thing that is ultimately their undoing.  Even without a stall, over a few years of running, the brush material clogs the commutator slots, current draw and heat go up over time, which accelerates brush and brush spring destruction, and the cycle continues until things get so clogged with carbon and so hot that the motor commutator starts melting or the coil wires burn, or the rubbery magnet thing starts swelling, drying out, flaking apart, etc. 

[wm3798]

I've been meaning to ask, Lee, I have an old Minitrix K4, loco only/no tender./box  It's been forever since I ran it, so I have no idea what it's doing these days, but if you want it, it's yours (as soon as I find it).


Bryan

I just happen to have a spare tender (or two) floating around.  I'll be happy to take it in here at the rescue...

Lee

[wm3798]

All good stuff here.
I'm going to proceed with the Mineaba experiment to see where it goes.  I'm hoping to have some tinkering time over the weekend.

My goals are to get the hind end of the motor to seat in the Rivarossi backhead, then go on from there to establish the needed length for the drive shaft to mesh with the worm gear, and the installation of the draw bar/power pick up peg at the bottom.

I have some micro plugs to take car of routing current if the OEM drawbar beg doesn't work as a power pick up, or to supplement it if it does.

I haven't been so bold as to send my steam era Laurel Valley markings out to be printed yet, but if this works, there will be a pretty good sized fleet at hand that will need some livery!

Lee

[Simon D.]

Silicon solutions.


I've been messing around re-motoring a Rivarossi Pacific using this motor: http://www.nigellawton009.com/MiniMotors.html available from here in the UK, which is nice and short.  I discovered that the motor chamber is 12mm diameter and the Lawton motor is 10mm.  So I got some cheap silicon tubing usually used for water tanks and the like, 12mm and 10 mm diameter.  The wall thickness is 1mm so the one fitted inside the other perfectly.  Then I replaced the universal with another small silicon tube.  I rigged this up to an old Kato Japanese loco tender for power.  Seems to work well, though I haven't really tested it under proper running conditions, and I don't know the real power/torque of the setup yet.


Pictures aren't brilliant, but I hope you get the idea.


Simon

[Simon D.]

Sorry link doesn't seem to work - http://www.nigellawton009.com/MiniMotors.html

[nkalanaga]

For thsoe who haven't explored it, here's the link to the "Loco Loco" site, where Randgust found his oddity:
http://www.douglas-self.com/MUSEUM/LOCOLOCO/locoloco.htm

There are some real weirdos there, among a few that actually make sense.  How about an electric steam loco, running a steam boiler off overhead wires? 
http://www.douglas-self.com/MUSEUM/LOCOLOCO/swisselec/swisselc.htm

Or a steam-electric loco that could match the FT diesel, in the 1890s?
http://www.douglas-self.com/MUSEUM/LOCOLOCO/heilmann/heilmann1.htm
http://www.douglas-self.com/MUSEUM/LOCOLOCO/heilmann/heilmann2.htm