Original Con-Cor PA-1 Motor

[Doug G.]

This "cup gear" (bell gear) system is utilized in the equally venerable Z scale MTL F7, which might explain why, although it's highly regarded as a reliable and sound puller, it also is often referred to as a "coffee grinder"...

Also, isn't it interesting that this thread has grown to 3 pages; that must say something, though I'm not sure what. 

Mark in Oregon

It's tribute to my superior foresight. Right.

I had no idea. I was just looking for a motor. I am thrilled, though, that there has been interest.

Doug

[Doug G.]

Not picking - just setting the record straight. 
I wish they still made those bearing blocks with brass inserts. The brass bearing tolerance was tighter than the plastic one, and the spherical shape of the brass insert allowed the bearing to self-align in the chassis.

I agree, Pete. I guess the plastic works OK as I have several, 20 years old, that are still as quiet as they were the day  bought them. C44-9Ws for example. I believe the most beneficial change was to make the bearing blocks square.

Doug

[randgust]

Having fiddled with the cup gear meshes in the Arnold GP9 (not your engine, I know, but...), I think the problem isn't the downward pressure or tightening of the mesh that is causing the problem.  The alignment of the motor pinions and cup gears just isn't that precise in these things, and you need some play in the gears to allow it to work.   If you are ever able to watch one of those cup gears on its axle going 'round and 'round, you'll see that it isn't perfectly concentric.  It's "pretty good", but there is definitely a little wobble to that cup gear.  So everything needs to be a little loose to let the pinion and cup teeth run over each other without binding.

Wow, I thought I was the only person to mess with Rapido GP9's and the cup gears.  It was kind of obsessive with me, I fabricated brass strips to wrap around the motor and hold it steady on the frame (drilled and tapped the brass strips to the frame top) and then paper-shimmed the motor around with the whole works running until I found the 'sweet spot' where it would quiet down.   I also used - heaven help me - Vaseline as the lubricant of choice because it was so heavy it would stay in place on the cup gear and spur.  Never damaged the plastic cup gear.   Used those two for decades and didn't retire them until I just got sick of how ugly they looked even with good paint and brass handrails, but they ran great - I'd turned the wheels, too, to a better flange and tread profile.   What we used to go through to get a decent-running GP anything.   Yup, Vaseline was great stuff on Rapido all-brass gears, it was so thick it would trap all the brass particles.  And you thought Bachmann could over-lubricate!

End result actually worked, it would run pretty smoothly and quietly, but wow, what an exercise.    Thanks for the trip down Bad Memory Lane, Max.

Also, FWIW I have a collection of what I think are second-generation PA1 motors - I repowered four Model Power RSD15's with them, and also repowered two Atlas GP9's (The Roco 'red gear' ones).   Those are really, really fine motors.   I have no idea if they are actually interchangeable with the first run, but they are some of the finest five-pole motors I've ever seen and they have been glued on the frames of my four RSD15's now for 30+ years and are still running just fine.

[strummer]

Wow, I thought I was the only person to mess with Rapido GP9's and the cup gears...I also used - heaven help me - Vaseline as the lubricant of choice because it was so heavy it would stay in place on the cup gear and spur.  Never damaged the plastic cup gear.   Used those two for decades and didn't retire them until I just got sick of how ugly they looked even with good paint and brass handrails, but they ran great - I'd turned the wheels, too, to a better flange and tread profile.   What we used to go through to get a decent-running GP anything.   Yup, Vaseline was great stuff on Rapido all-brass gears, it was so thick it would trap all the brass particles.  And you thought Bachmann could over-lubricate!

Interesting. In an effort to quiet down the Z scale F7s, I did something similar; I used La Belle "Grease", and put a bunch inside both cup gears of one of my units. It did noticeably quiet things down, which led me to believe that a lot of the noise was coming from the drive train. I eventually cleaned it all out, but just for laughs I may pick up a small jar and Vaseline and try it, since it is thicker than the grease I used...

Mark in Oregon

[Doug G.]

I agree they are great motors (the Con-Cor second PA-1 version). They aren't interchangeable with the first version, though. The first version is made more like other conventional motors with the magnets on one end and pole pieces extended over to and around the armature. It's a lot longer and squatter than the second version. A fine motor in it's own right.

I know what you mean by efforts to make early N scale run acceptably. Note that I said acceptably, not necessarily excellently.

Doug

[Doug G.]

You can even use automotive wheel bearing grease and it will do no harm, at least on the Con-Cor diesels. The cup gears must be made of a plastic not affected by petroleum.

The grease acts as a damping agent to keep things from vibrating around.

Doug

[Doug G.]

Thanks to Max, I was able to obtain a Sagami 1225 motor to install in my one PA-1 with a ruined motor:



It was relatively easy to modify to slip right down into the cavity/pit into which the original motor fit. A fairly thin spacer at the bottom got it to the right height.

I apologize for the lousy picture but my camera quit on me so this is a scan. My present scanner has nowhere near the depth of focus my old one did.

Doug

[peteski]

Thanks to Max, I was able to obtain a Sagami 1225 motor to install in my one PA-1 with a ruined motor:

It was relatively easy to modify to slip right down into the cavity/pit into which the original motor fit. A fairly thin spacer at the bottom got it to the right height.

I apologize for the lousy picture but my camera quit on me so this is a scan. My present scanner has nowhere near the depth of focus my old one did.

Doug

Excellent!
As for your scanner comment, isn't it always the way?  The new-and-improved is not always the case.

[Doug G.]

Yeah, my old scanner easily focused from close up to a half inch (about the depth of the motor pit in the PA), and more away. Most of the images on my site are scans from my old one and they're fine.

Doug

[wishj]

Hi Doug  where did you obtain the sagami motor  as I have a couple pa’s that need remotering John

[mmagliaro]

How does the PA run with that Sagami in there?  Is it better than the OEM performance?  About the same?  Worse?

As for where to get these, I had a few in a "stash", which is where Doug's came from.  You can't buy them anymore - they haven't been available for some 20 years.  Sometimes they pop up on eBay, but it's getting rarer and rarer.

You could always go with a Mashima - those have double 1.5mm shafts and are made in very similar sizes to the
old Sagamis.

[Doug G.]

Yeah, mine came from Max. As he said, a search may turn up similar motors.

The PA runs almost identically to the ones with original motors in them. The starting voltages and speed curves are very similar. In fact, I have been double heading the Sagami-powered one with a Sekisui-powered one and they run very well together.

I was actually amazed that ended up being the case with two different motor manufacturers/configurations. Who knows, though, Sekisui (Kato) may have had Sagami make those motors for them back then.

Oh, and the width of the space the right half of the motor (in the photo which would be considered the front of the motor, normally.) is fit into, is 11mm. I could have mounted it the other way around since the motor/shafts are basically the same on each end. The "front" just has the terminals on it. Then the motor could be right-side-up as mine is upside down (note the mounting holes). I did that to match up polarity so I wouldn't have to run wires across the chassis.

However, looking at the photo again, It's easier to do it the way I did as there is much more room at the rear of the opening than at the front, for the terminals/wires .

Doug

[PGE_Modeller]

Late in reading this thread, but just checked my stash and I have one of these motors and 2 of the shafts each with the worm and 2 plastic bearings, but only one of them has the cup gear.  Motor ran when tested.  Motor dimensions match those posted by Doug to +/- about 0.1 mm.  If anyone needs/wants one, PM me with ZIP/Postal Code and I'll get a postage cost from Vancouver, BC.  I no longer have a Con-Cor PA-1, so the motor is available for the cost of postage and a padded envelope or small box.

Cheers,

[Doug G.]

I did find out that using a heavier grease (actually, I  have known this for a long time) in the cup gears quiets the mechanism right down - until the grease gets flung out of the gear. Then it returns to a noisier condition. I plan on trying STP or silicone damping fluid instead of regular wheel bearing grease to see if those will stay in place.

Doug