Arnold S2 remotoring, what's the final verdict?

[wcfn100]

  I'm finally getting around to completing a couple of CGW S2's and would like to upgrade the motors.  I know there was a kit but it is no longer available.  I'd like to know what to ask for from the motorman if anyone has some suggestions.


Jason

[Chris333]

I used a Mashima 10x12x15. The springs need to be pretty much perfect for it to be smooth.

The stock motor shaft is some goofy size, the mashima is 1.5mm. I used bits of the stock motors shaft (since it fits the springs perfectly) I had to sleeve the shaft down.

[wcfn100]

I used bits of the stock motors shaft

What does that mean?

Jason

[Chris333]

The stock motor shaft is a odd size. Can't remember exactly but it was like 1.19mm or something like that. I know the springs would not grip a 1mm shaft I had. So I cut the mashima shafts to about 1/8" long. I used a short piece of 1.5mm ID tubing over that, about 1/4" long (guessing on measurements). I took another piece of tubing with a 1.5mm OD and reamed the inside till the stock motor shaft fit in it. Slid that tube into the larger one and glued it all together. 

I was able to whip up this ultra technical drawing ;D


One of my springs was a bit deformed, but it still ran good. Since I change projects every other day the chassis ended up under a HH660 I built. This is what is left over from the S2:

I soldered brass wire to the motor so the circuit board contact would touch. If you do it just like me your will run backwards from all others  :

The motor is just held in there tight with a piece of paper around it. There is a thin shim under it to keep the shaft centered where the original motor was. I forget the thickness, but measure the stock motor (say 16mm) the mashima is 15mm so you need a .5mm shim.

Anyways that's how I did it. Sorry I don't remember more.

[wcfn100]

Hey, that's great.  I think the shaft size is going to be problem with every motor.  I'm going to E-Mail the Atlas parts department to see if they have any of the MP15 motors which look like they will fit.  I don't know the shaft but I doubt it'll be 1.1mm or less to fit the springs.

Thanks,

Jason

[Chris333]

MP15 motor    don't tell Victor...

They are the same size, but the Atlas motor is 3 pole with wipers. The one in my S2 is a 5 pole with brushes. I did take it apart and post pics a while back, but the pics are gone.

I don't think it will matter though, just pullin' your chain.

[wcfn100]

Since these replacement motors are shorter and the shaft size is wrong, I wonder if there's enough room for some sort of flywheel with a 1.1mm nub for the spring or maybe something to capture the outside diameter of the spring.  I'm sure you thought of all this, I'm just thinking out loud.

As for the poles, I remain unconvinced about that whole topic.  I get all the thoery but haven't seen enough 'proof' to pick a side.  As long as it's better than what I'm replacing, I'm good. 


Jason

[daniel_leavitt2000]

At one time NWSL made 5 pole armatures of various sizes, including a direct replacment to the 3 pole one used in the S2. If I recall, there was an improvment of performance but the Mashima option is better. The Faulhaber motor used in the N-Stars kit is no longer available I belive. Man does it run nice though. Mine tops out at about 65 MPH and its low speed performance is better then the LL SW1200.

[Chris333]

Jason,

The "motorman" did cut me a flywheel to fit over the bigger tubing sleeve, but he screwed up on the diameter so it didn't fit (he did it for free anyways), but yes you could fit one in there. You could also use the 20mm long motor, you get less space to play with though.

The one in the pic above did run like a LL SW. It was a bit loud, I think because of the one bent spring.

[Mark5]

As for the poles, I remain unconvinced about that whole topic.  I get all the thoery but haven't seen enough 'proof' to pick a side.  As long as it's better than what I'm replacing, I'm good. 


Jason

With 30+ years of playing with N scale motors - I am firmly in the "more poles is better" camp. You can improve the performance of a 3 pole, but all other things being equal more poles is still better at slow speed. That said I am sure many newer 3 poles are better than some older 5 poles.

My new Bachmann J's have 3 pole motors. They run nice with my new fancy electro gizmo DC powerpak, with low speed performance being adequate. The three poles still rear their ugly head with slight "cogginess" at the slower speeds (trains don't rocket start) - but not enough to make me want to re-motor them. If I use my old 1970s MRC 500N powerpak the loco is a jackrabbit.

So with a newer bells and whistles powerpak I can offset most of the crappy characteristics of the 3 pole.

DISCLAIMER: I have not operated the Atlas MP15 or any of the newer Kato 3 polers (The GS4 has a 3 poler! )

Mark

[Ryan87]

"more poles is better" camp.

/>
 ;D

Seriously a five pole motor will always have better performance than an equivalent three pole.
Mind you the more modern Three pole motors run a hell of alot better than some of the early five pole "replacement" motors I've seen. (which admittedly isn't very many)

is there a readily available source for seven pole motors? I'm sure I've seen a Kato NW2 conversion somewhere...

[Mark5]

Although 5 poles is markedly better than 3 poles (all other factors being equal), I am of the opinion that the law of diminishing returns applies here: 7 poles won't yield as much of an advantage over 5 as 5 over 3 does, and so on.

re the vid:  ;D

[Ryan87]

Although 5 poles is markedly better than 3 poles (all other factors being equal), I am of the opinion that the law of diminishing returns applies here: 7 poles won't yield as much of an advantage over 5 as 5 over 3 does, and so on.

I brought it up because I remember somewhere (A board?) reading that by replacing the motor in a Kato NW2 with a seven pole, the fly wheel could be eliminated adding more room for weight.
I have no idea if it would work, and was wondering if anyone has tried anything similar...

[Mark5]

Interesting, I didn't know there was a seven pole that size out there.

[Chris333]

Yeah, most Faulhabers have 7 poles. They are coreless so don't really have poles at all, but they have 7 different "fields" around them that is the same equivalent.

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Besides a Faulhaber motor it also has a 4:1 gearhead.

My biggest problem with the Kato NW2 is it's high speed. If they would have geared it down more I would of gladly left the 3 pole motor in there.

I knew mentioning poles would get things crackin'  ;D