Re-motor O scale KTM NYC Mohawk help!

Pitch the open frame, ….go with a can motor, preferably a Pittman, …..Mohawk cab space is tight ….measure cab dimensions and we’ll see what we all can recommend, …..9433 might fit, but maybe too tight??…9432 is a short fat stubby motor that should fit with ease, …some modification under cab may be necessary to clear a large enough flywheel for DCS, ….

Pat

I'd pay attention to Pat, he's the Pittman re-motoring expert!

I agree with Pat.  Pittman 9432s are pretty rare in my experience.  By the way, assuming there is space, all that you really need are a couple 6-32 screws, two washers, and some vacuum hose to put in the Pittman.  

Excellent, thank you all!  Now to see if I can find me a 9432 or 9433.  Hopefully they come with a flywheel already attached, albeit it should be a thin one to fit my allotted space.  I'm diving into this same project now with a KTM Niagara.  I just removed the boiler and lo and behold it has a Pittman can motor.  Now to find a flywheel to fit this monster!

While I'm still on this thread, where is a good place to find one of the Pittman motors we referenced?    If I have to look on eBay I will, but didn't know if there was a better way to track on down or not.

Thanks again!!!!!

Lionel has 9433 Pittmans along with a few flywheels with 4mm mounting holes. Not sure there are any thin ones though. The ones they have mount on the drive side and come with couplings for dogbones or U joint drive shafts.

Actually Lionel also has something they call a “fixit flywheel”. Its thin but made for a smaller shaft. Its comes with a set screw and only has to be opened up with a 4mm drill.

You can find these parts at lionelsupport.com

Use search terms “Pittman”, “flywheel”, “fixit” or “fix it”

Pete

Rick

Sure would like to see some pictures...🙂

Mark in Oregon

MTH used a 9432 Pittman in several models, ….after Pittman left the industry in search of bigger fish to fry, MTH had a vendor build a knockoff very comparable to a Pittman ……biggest thing is, dimensionally, it’s identical to a 9432,…..I don’t see any available at the moment, but I know inventory is still being added on a regular basis ……that would be an ideal candidate for tight cabs like a Mohawk, etc,…

Pat

Pat,

I did not know that about the MTH Locos and the 9432. Good info, thank you.  

Rob

My opinion is if I have a good running loco,  I don't replace the motor or gear boxes etc.    I have a number of KTM locos from both MG and USH.    The MG ones generally run a little slow, and I have replaced motors in them.   However, I have not replaced motors in the USH locos.   They run fine, and once broken in, are very quiet and smooth.    The "newer" KTM motors in them are really quite nice.   

I check the amperage and generally it is under 2 amps running.    the exceptions are very loads and very large engines/motors which might draw 3 amps or a bit more under load.  

these currents are not a problem with straight DC.    When I used straight DC, I had 6 amp GML throttles that easily handled that.     Now with DCC, I can find any number of decoders that are rated at 4 amps or more including sound ones from SounTRaxx.    My favorite for motor control without sound is the NCE D408SR.    It is rated for amps continuous and the newest release is rated 10 amps stall. 

I am not familiar with DCS but I would think if they want to be in the model RR business they would offer a range of decoders for a range of loco requirements.

@prrjim posted:

My opinion is if I have a good running loco,  I don't replace the motor or gear boxes etc.   

There's a lot to be said for this...

Mark in Oregon

Open frame motors don’t lend themselves to DCS. Pittmans and their Chinese knockoffs have seven poles vs three in a typical open frame motor. No comparison in torque either.

Pete

I’d agree with Pete, if you’re gonna operate them, and you’re into scale fidelity, then they should run in scale fidelity as well,….I can’t see an open frame motor behaving anywheres close to a large can motor in a DCS or TMCC environment……

Pat

I have to sing with the chorus here, forget the open frame three-pole motors if you want decent running, especially at low speeds.

Well   I have never seen a 3 pole KTM motor ever in a KTM model, their 5 pole or is it seven? think it's seven. I did swop out the magnets on one and replaced them with rare earth magnets. It would pull the wall of your barn, stalls out at just over two amp's. O! I also lightened the spring tenshon on the brushes. I was going to replace the bearings with ball bearings, maybe soon! These really are the basic differences between an older open frame motor, and a modern can motor, except for a skewed armature, some times! DCS! try adding a plastic drum, press fitted on the shaft, and add your tach strip, no real need for a fly wheel. If your really adventures, try playing around with the rare earth magnets, TESLA style, you'll get some interesting results.       cTr...( Choose the right )

Like many have stated I did not think much of open frame motors. Even  new they seemed noisy, certainly inefficient.  That is until I bought a  KTM/Westside loco.  It has an open frame motor that is remarkably quiet and runs at about 0.7A of current. Current draw is not as good as Pittman but still not bad.  I think Mr. Bloy has made some good points about open frame designs.  Some inspiring ideas with those with rare earth magnets....

I agree with Mister Bloy about 3-5-7 pole.    I was pretty sure the KTM motors I had were not 3 pole.    Mine are not either.

As for noise, that is sometimes caused by brush spring tension being too tight, and sometimes just because the motor is new.     A little running solves the "new" problem.

Having never had a KTM motor in captivity, I'll bow to the details of it's construction and performance.  However, 99% of the model train people that encounter the open frame motors are going to be looking at the 3-pole Lionel motor.  I can personally attest to the unsuitability of the Lionel open frame motor for precision control.

@prrjim posted:

I agree with Mister Bloy about 3-5-7 pole.    I was pretty sure the KTM motors I had were not 3 pole.    Mine are not either.

As for noise, that is sometimes caused by brush spring tension being too tight, and sometimes just because the motor is new.     A little running solves the "new" problem.

I think you’re correct about the noise.  Nearly all the KTM motors in my possession were new and probably needed to be broken in.  Glad I still kept them.  Thanks for the insight .

Over the years I’ve owned many KTM (MG, USH).  locomotives powered with open frame motors. While they ran reasonably well at track speed their performance was lacking when starting heavy trains (slight lurch).  The old open frame motors have relatively low torque and high current draw when compared with similarly sized can motors.  My recommended upgrade for optimum performance is to remoter with high torque rare earth magnet Pittman can  motors.  The current draw and noise factors are particularly important if you later decide to go with digital control and sound.