A LOOK INSIDE A PITTMAN MOTOR

gunrunnerjohn posted:

Casey Jones2 posted:

All that's happened is the commutator has been pushed towards the armature as those are 2 separate pieces. Using a jaw puller the commutator can be pulled back into position and all end play eliminated. Pull the commutator until the windings are tight then assemble motor with factory shims. If armature won't spin then tap the armature shaft with a hammer until it spins and end play is correct.

Excessive end play is usually from dropping motor on armature shaft or incorrect pressing on of flywheel, u-joint etc. Have to press against the armature shaft and not the motor housing.

Trying to pull the commutator down will likely result in more issues than simply shimming it at this point.  I agree that it probably happened as the result of a drop or other impact, already said that.  There's no easy way to grab the commutator without damaging the connecting wires.  Since the motor can be made to run quite nicely shimming it, I'd go for the safe option and not risk ruining the motor.  Also, the shims are much easier to do.

Have you ever tried pulling a commutator? They slide back into position real easy by using a small 2 jaw gear puller. Just tightening the forcing screw by hand will pull them back. I've been into over 100 of these gearmotors drilling into the commutator end of the armature shaft and then threading them so I can mount a flywheel.

Like this....

Threaded for flywheel securing screw...

With flywheel mounted...

No offense Casey, but your tools and skillset are probably vastly different than the normal guy working on these.  I didn't say it wasn't possible, I just said it's likely to do more damage then simply using shims, and I stand by that comment.  You may have the skill and the tools to do it, I know I don't have anything like the tools you obviously have at your disposal, I wouldn't try it.

Drilling and tapping the armature shaft for the flywheel is not required to just pull the commutator with a two jaw puller. That was just a red herring or thread drift within the same thread drift post.

The guy handing out programs to follow this thread must have ducked out of the building.

Pete

I

The Williams Crown Edition steamers were made by Samhongsa / SAMtech, a company with a lot of experience in HO scale brass.  These were excellent designs (although I would replace that 3-pole RS-550 motor with the equivalent 5-pole RS-555 motor.)  IMO this is how a scale steam loco should be built.  If you can graft a brace like the one in Pete's (Norton) picture onto the gearbox in the Lionel Niagara, most of your problems will be solved.--------------------------

I have a Weaver GS2 with this same RS 550 sh motor and would like to know where to get a replacement or upgrade RS-555 motor. I have tried several places and they mostly have Pittman motors. Should I consider a pittman? WHat model Pittman?

Thanks

Oldcarsrule posted:

 

I have a Weaver GS2 with this same RS 550 sh motor and would like to know where to get a replacement or upgrade RS-555 motor. I have tried several places and they mostly have Pittman motors. Should I consider a pittman? WHat model Pittman?

Thanks

 

 

Search on eBay. There are many Mabuchi RS-555s available for small money.

Pete

So , is the armature shaft a soft steel?

I thought it was hardened .

Andre.

How to know what specs  for replacing. The ones on Ebay vary in volts and RPM (4000 to as high as 8600) ?

Most train motors are 12V. I see two different shaft lengths. The Williams pictured has a flywheel held on by a set screw. If your engine has a pressed on flywheel, swapping out will not be as easy.

Andre, the torque brace is minimize the thrust force on the motor armature as there are no thrust bearings. In addition the Williams engine has a sliding U joint so thrust force is zero. On the Lionel engine there is little play in the U joint (one reason they break) and no torque brace so the armature and commutator take all the force. Early on Alex pictured an armature where the commutator had moved on the shaft giving a large amount of play.

Pete

Oldcarsrule posted:

How to know what specs  for replacing. The ones on Ebay vary in volts and RPM (4000 to as high as 8600) ?

I have one if you needed, you can contact me via my profile.  I bought 2 when I converted my Williams J to the 555 motor.  G

G, if Oldcarsrule doenst take the motor id be interested. Ive got a Williams J that I need to get back into and change the tach tape to get a better speed and chuff rates while im in there, I can give her a motor upgrade