I’ve expressed my interest in the Alco RS-2. My fleet has grown somewhat. I now have 7 of the critters… 3 of the AHM variety, an Athearn RS-3 (Advertised as an RS-2, but what the heck?! ) and 3 - Alco Models Brass units.
The first Brass unit had the infamous Sagami putty installation and slipping U-joints. The second was all original with a shorted KMT open frame motor (Grrr) and the third had a can motor installed. Haven’t opened this one to see what was done but it seems to run well and I’m happy.
My question involves the KMT motor. Does anyone have one of these they might want to part with… yeah right!
OR… is there someplace I can send the KMT to be rebuilt? Probably not cheap, but I can always ask.
In my opinion unless you can confirm ‘collector value’ in having the KMT, I’d swap it out for a modern can motor.
Without seeing the specific KMT and installation, I can only refer you to places like eBay to find a compatible replacement if anyone here doesn’t have one cheap. You will without a doubt want to replace the factory magnet in it with a modern NIB or similar high-strength magnet (and people here can advise how best to do that).
With your other interests and skills, it might be possible for you to rewind the motor if in fact it has been fried, and get a set of agate balance rails from eBay or set up a knife-edge arrangement to poise the armature afterward.
People here might weigh in on the current value of using a coreless motor as an option. I’ve been a lover of these in models since being introduced to them (by MR) in the very early 1970s.
Oh… collector value doesn’t concern me much. It’s just that I’d like to have the original setup. I’m odd that way… well, probably in many other ways as well!
I might go with a can motor for the first RS. I’ve watched some Youtube videos on the topic. Seems a “relatively” painless process. Just figuring out a mount for it!
Actually, I did think of rewinding the armature but common sense got in the way.
WAY back in the day I was into slot car racing. I had a spare Mabuchi and I thought I’d just rewind it to see if I could get a few more RPM’s. BOY did I. That li’l sucker screamed… for about 2 minutes. Then it let go with the magic smoke.
I have an Alco Models H20-44 road switcher (ca. 1981) that has a Taneda can motor. While I was initially able to get some impressive slow switching out of her (0.25sMPH) after a good cleaning and re-lubing, the gear towers were very noisy and had quite a bit of slop to them; thereby making them more challenging to maintain so that it ran well reliably. After some discussion with NWSL, I’m looking at completely replacing the towers and motor and going with Stanton drives.
If it’s just a simple motor replacement I wouldn’t hesitate one whit to do that. You can always keep & store the original “setup” should someone be interested in it. I would be much more interested in it running well…but that’s just me.
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I like KMT’s drives for the most part, but the motors have been kind of hit and miss for me. I tried rewinding and doing a magnet upgrade on a dead one a few years back, and although the winding turned out fine, the magnetic field in these motors is very difficult to replicate (top and bottom magnets polarized on the sides; I think they’re magnetized after assembly). I ended up replacing it with a can motor.
My first one works smooth as glass with no more than a tune up now and then, so I was happy to keep that one in place!
Another one still worked, but it was so off balance that I couldn’t use it. The amount of vibration it caused was actually shaking various solder joints apart over time!
The motors arrived on Friday. Thank you so much!
I have one of them in the frame of RS-2 #2. Just looking for the shafts that go between the motor and truck towers.
When I take something apart I put the (small) parts in a container so they won’t get lost. Well… I’m sure the shafts aren’t lost… I just don’t remember where that small container is stashed. (I’m old. That’s my story. I’m sticking to it! [:)])
I presume there are two sleeves per end, and that the intermediate shaft ‘floats’ between the two. Also that the swing is little enough that the sleeves don’t see too much compression.
What’s the minimum radius on that DES-3? Doesn’t look to me to be the poster child for the kinds of radii the prototype would be expected to negotiate…
The only thing that limits the radius is the cut-out in the frame where the gear tower passes through. My minimums, even in yard trackage is at least 28" although I do have some #5 turnouts.
The short wheelbase of the DES-3 negotiates these with ease.
Yay! I got the motor in my RS-2 #2 this afternoon. AND… poop. The bottom (plastic) gear on the rear truck seems to be short 3 or 4 teeth. I “might” have something around that’ll work. I have a lot of plastic gears left over from odds and ends of robotic projects. Some calipereing and micrometering will be called for.
Sadly tomorrow marks the end of my precious days off. Back to the salt mines! Bleah!!!
If you can’t find a gear that works, NWSL makes gears specifically for KMT drives like the one in your ALCO. I’ve used some, and they’re better than the originals!
) and 3 - Alco Models Brass units.
