can motor for post war lionel...726/736 Pullmor replacement

With better gearing, the smaller Mabuchi RS-385 should fit in many, and it wouldn't be working that hard with more mechanical advantage.  You can move a mountain with a small motor with the proper gearing.

 

Anybody know where to get dimensions on the current design? Like maybe a drawing for a 681-100 motor?

For what it's worth, the 624 with Timko motor and standard gearing, with PS2 installed, can cruise at 3 smph.

Problem with thePulmor is that it has a three pole armature, which causes varying torque.  Can motors have more poles, resulting in smoother torque.

This 624 used to have internal rectification and filtration, to run the Pulmor on dc, and that was a bit smoother than ac.

On most gear-head motors (those having an external planetary), the output shaft is offset from the center line of the cylindrical "can" (motor body.)  This isn't a bad thing.  When you think about the profile of a pullmor motor, the field coil on the back side protrudes much further from the shaft than the poles do from the front.  So using a gearhead motor might actually improve your mounting options.

 

However--the last time I checked, mass-produced gearheads begin at 7:1 which would make the resulting loco too slow.  And if the gearhead motor ever fails, you would have to find an identical one to replace it.

 

There has to be a way to build or retrofit a complete "power package" that achieves greater gear reduction, and still fits within the envelope of the existing chassis.  In looking through some junk boxes, could the can motor chassis in the current Thomas the Tank Engine be a possible substitute for the parallel plate motor in a 2036?  The tough part would be locating new mounting points.

 

It's a shame the 1946 model 726 is comparatively rare and valuable, because I can see these being easier to upgrade than the redesigned model widely sold after 1947.  

I also know that Northwest Short Line (NWSL) sells ball-bearing gearboxes in both idler and direct-drive configurations.  Maybe one of these could contribute to the solution?  Just brainstorming aloud here.   -Ted

 

While not optimum; I leave all of the old Pulmor stuff alone. Now if someone made a direct "drop-in" replacement 5 pole armature for these motors, the performance would increase and better slow speed torque and smoother operation would result. I am  surprised that no one has tooled up to make one. They would probably be a popular upgrade, a good seller, and if you ran it on DC, further improvement would result.

I have wondered about the armature also and agree...why is it not an aftermarket part? Pretty sure there is profit potential there for some one who has the means to make it happen...maybe even an offshore manufacturer...I would have no problem at least investigating if I could get specs on the part...surely there exists a drawing...and it would not be difficult to communicate the revision to add the additional poles...just make it the same as this 3- pole one except make it five pole...

I had two old, cheap cordless drills and the batteries died. Too expensive to replace. One day I tore the drills apart and salvaged the can motors, reverse mechanism and the reduction gears. Just in case I wanted themfor a project. It was a nice planetary gear set in them but don't have specs on them Anybody ever play with anything like that ??  I have a smaller rechargeable screwdriver that I have never used which s going to be examined too.

You may be on to something there. There are gazillions of those Skil & Craftsman cordless screwdrivers around with dead sub-C NiCd batteries.

quote:

It's a shame the 1946 model 726 is comparatively rare and valuable, because I can see these being easier to upgrade than the redesigned model widely sold after 1947.

 

1946 Berkshires run fairly slow already.

I opened up my old(made in Mexico)  Sears rechargeable screwdriver  and it has a planetary gearbox on the end of the motor which I held on with plastic tape. At the widest point, the gearbox, it is 1 1/2" and a length of 3 1/2" but that includes the holder for the screwdriver bit which can be shortened about 1/2". The bit holder would make a nice coupling. At about 18 volts it was turning pretty good with good torque. I ran it for awhile and didn't seem to be heating up too much  The battery is long and didn't ry to charge it and measure the voltage although you can cut it open nd count the cells. I think putting one of these motors in a Lionel is possible but can't vouch for how long it would last. Wit that bit holder on the shaft hooking it up should,t be too hard. Someone should see what they can do. right now I don't have a loco to use but will look for one. Have fun.

I have repaired several of these. It was an alignment issue and also a material issue.  MTH still uses the design successfully on newer tinplate.

 

To me this is about side plate motor or the direct gear drive.  Most people value the 727/36/46 more than side plates like 2046/55/56.

 

For MTH Imperial steamers like the J, or Williams or 3rd Rail they use the 545/550 or 555 motor.  More torque then the 385.  Or they use a Pittman, and there is a Shorter version of the Pitman too.

 

The easier issues would be to have a motor built to work, but there may be limitation to how much torque it can have at low speed, or the price to have that characteristic goes too high.

 

From a personnel perspective, I can't stand seeing the DC Can motor sticking out the back of the Cab.  G

You're right. That will cause the engineer and fireman to run right to Human Resources with a fistful of complaints.

I replace the batteries in these, my Craftsman and Ryobi ones with the internal batteries are both on their third set.  Never thought of powering my locomotive with them.

From a personnel perspective, I can't stand seeing the DC Can motor sticking out the back of the Cab.

 

You're right. That will cause the engineer and fireman to run right to Human Resources with a fistful of complaints.

 

 

 

And, if equipped with PS2 and the tach tape, the engineer, foreman, and operator complain to OSHA that they get vertigo.

 

Ted, I have one of the 1946 726's.  It's by far the worst-running loco I have ever had.  Noisy, and it requires a constant hand on the throttle.  For info, it's motor wasn't called Pulmor, but "Atomic."

Home construction of a gear box will be much harder then mounting a motor.  G

quote:

Ted, I have one of the 1946 726's.  It's by far the worst-running loco I have ever had.  Noisy, and it requires a constant hand on the throttle.  For info, it's motor wasn't called Pulmor, but "Atomic."

 

I've had six of them pass though my hands. Some ran better than others. A fellow repairman told me that in order to get them to run smoothly, the bearing blocks needed to be shimmed. The last 1946 Berkshire I purchased runs very smoothly. I took a look inside to see whether the bearings had been shimmed. They were not.

Check out this web page https://www.servocity.com/html...s___accessories.html .

 

They might have a gear motor that could work.

The question sounds to me more like an intriguing tinkerer/engineer's interest rather than a solution to a more-or-less non-existent problem, if original style repro parts and Williams engines are available.

A collection of motors may be found in the catalogs of several electronics supply companies.  For example, see page 83 of the Jameco catalog, at www.jameco.com.

 

CW, just what gets shimmed on the 1946 726?

 

 

quote:

CW, just what gets shimmed on the 1946 726?

 

On the 1946 Berkshire, each wheel set is mounted in a pair of bearings that go into slots in the chassis. The collector plate serves as the bottom of the chassis, and holds the bearings in place. On all of the 1946 Berkshires I have owned, the bearings can move around a bit in those slots, but the axles were not sloppy in the bearings at all.
The fellow recommended shimming those bearings in the slots, but he really did not go into details of exactly what to do. (He was a machinist, and had a reputation as an excellent repairman)

I just checked the one that runs nicely. I don't see where the bearings on this engine are any tighter than any of the other 1946 Berks that I have owned.
So, I am at a loss as to why this particular engine runs so well.

 

Since I didn't quite follow what he said had to be done, I never tried shimming my engines. If anyone has a better explanation of what has to be done, perhaps I'll try it on one of the ones that doesn't run as well.

Thanks, CW.  Some day when I have a chance, I'll have to examine it.

 

One issue with these old worm gear locos (not the 1946 #726) is that the side rods are the means of transmitting power form the rear axle to the others, which requires greater accuracy in quartering  and can cause problem at the parts wear.  My 1950 736 has a binding issue that defies me when I tray to ascertain the cause.  I've already replaced axles and the spur gear, and bushed the side rods to eliminate slop and play.

Only if you're into REALLY slow operations.

 

303 RPM full speed, 16/1 locomotive gear ratio, and 1.25" drivers.  You get 75" a minute, or about 1.25" a second.  You'd have VERY smooth operation, but very slow running.

 

Nope...not intended as engineering exercise...but wondering if the pw stuff could be made to operate, via some existing or easily created method, to operate like late model stuff...as in slow, smooth, speed relative to scale way...steam engines generally don't run 60 or 70 miles an hour in real life unless it's a pacific on a long straight stretch..
Just wondering if someone made it happen and how...I don't have highly collectable examples,  just runners, so don't have a problem changing things if the results are worth the effort...

I would like my old lionel berk to run a steady 10 miles an hour with 15 to 20 cars...reliable...and for a long time...

...in scale speed, of course...

I suspect something could be done with gear motors, though even with the early locomotives with 8:1 gearing, you'd need a gear motor that perhaps has a 4:1 gear ratio to give you 32:1 total gear reduction.  Assuming a top speed of the motor at 6000 RPM, yielding 1500 RPM at the output shaft, this would give you a nice one foot per second top speed.  You'd get really smooth low speed performance, especially with cruise control, all we need it the proper gear motor that will fit in the chassis...

 

For later models with higher gear ratios, you'd need a faster shaft output to attain reasonable speeds.

Gibson man, my 736 Berk, with PS2 and a Timko motor, will do the 10 smph.  Unfortunately, until I find the binding problem, at slower speeds than that it tends to hop.  As to pulling 10 cars, I doubt it since I have grades.  I have found that my 624, which does run smooth at slower speeds, doesn't have the pulling power of traction tires locos.  Both have magne-traction.

 

You're right about slower speeds being the norm.  I grew up in northern NJ, and in the summer could hear every chuff of the NYC locos 4 miles west.

 

Grj, the problem is space.  Some of the motors in the Jameco catalog look like they have possibilities, but I'm not going to bust the budget on buying motors that may or may not fit, and then there's the problem of getting worms and matching spur gears.

Correct, I'm not ready to take on that project, plenty of locomotives that I can upgrade that look good and have decent gear ratios.

 

I came across this source for planetary-geared motors:

 

http://www.sei-automation.com

 

Probably a 3.7:1 or the 5.2:1 would be the only reasonable choices.  I'll wait for the mechanical wizards to get this running...

 

 

I talked with a motor designer a few years ago about the problems with PullMor motors.  Since the PM motor has three poles on the armature and two on the field, it has a2:1 variation in the torque curve which is why it is impossible to get it to run smooth at low speed.  The designer suggested gluing thin pieces of steel (like from a tin can but not a soda can) between the poles of the armature to smooth out the torque curve.  I haven't tried it but it doesn't sound too difficult.  If this indeed smooths out the torque curve, the back EMF of the motor could be used for speed control, or it might be possible to add a encoder tape.  I haven't done anything with this information yet due to lack of time.

No offense, but I think the DC gear motor retrofit has more promise.   "fixing" the torque curve of the Pulmore motor still doesn't solve the gearing issue.

 

Experience has shown that if you want a silk purse, it is better to start with the web of a silkworm than the ear of a sow.  A 3-pole armature is, as servoguy points out, inherently not a smooth operator.  There is only so much that can be done with it. Better to start with a motor having more poles and going from there, to yield a better result.

Someone asked about where to get gears.  Stock Drive:  https://sdp-si.com/eStore/Catalog  They have anything you can imagine.  

I am trying to figure out how to get a can motor into a loco like a 2055.  Space is at a premium.

Gosh servoguy, since your post is specific to the 2055 Lionel might already have done what you're asking. The boiler casting of the new LionChief Plus Pacific is VERY similar to a 2055.  A little dull grey on the driving wheels and a rubber-stamped number would get you darn close!

 

Maybe Neil Young will read this thread and have pity on us poor nostalgic fools.  I hope the next item in his Signature Line is a postwar steam loco with LEGACY!  And yes Lionel, please keep the back-drivable gears!     -Ted

 

RJR, Not all DC Can motors used in Trains are 5 pole.  Some have been 3 pole.  Any motor ending in 0 instead of 5.  540 and 550 come to mind.

 

Servo why not try replacing the field with permanent magnets.  Make a slotcar like pancake motor out of the side frame motor. 

 

Thanks for that link, looks like some gears available to fix MTH engines without having to buy a new chassis.   G

There is no good reason today why a decent motor combo couldn't be found to upgrade a toy loco. It would boil down to the old question of time/cost/ benefit or "is it really worth it".   Better yet, "I just want to see if I can make it work". That is the fun part.

Thanks for that bit of info, GGG.

 

And thank you, servoguy, for that link.  A 1543-page catalog is a lot of confusing material---I can't even find the price list.  I'm sure that what I think I might need is in there somewhere.