I am repairing a 627 44 tonner right now, and Im have quite a bit of problems wiith the motor in it right now.
but i still am having problems with getting it to move. I replaved the armerature bearing plate and bearing then I got it all together.
So I put it on my test track, but it will only move in one diection ( E-unit will cycle but not reverse motor elctricity flow, making the sequence go neutral-neutral- neutral- forward)
And when its in that direction, it will hesitate to move, then i need to crank the tranny to 14 volts to get it to move
Then it makes a terible grinding noise and it will jerk slowly forward.
The field windings and arm. Then get warm very quickly .
Mechanical: Can you make the wheels turn by turning the armature by hand? It’s not that easy, since only a small part of it shows through the gap between the pole pieces; but it should move easily, albeit slowly. Then can you make the armature turn by turning the wheels. This takes a lot of force, and some locomotives are just too stiff; but, if it turns (both ways) there probably isn’t a mechanical problem. If it turns only one way, that might mean a thrust bearing problem, since the armature thrust reverses with the direction of operation.
Electrical: Is the e-unit wired correctly? The blue and yellow should go to the armature, the green to the field. You can bypass the e-unit by simply wiring the armature and field in series, to verify that the motor itself is okay.
If it makes a grinding noise is it probably mechanical. If it heats up the motor doesn’t run free. That can also be because the brushes are too short or worn in an angular shape, blocking the motor in one direction.
I would remove the motor (It’s clamped in the truck, should loosen if you pull the motor up, or force it to move up with a screwdriver.) Then test the motor and reverse unit. It can also be that the worm drive is worn and blocks in one direction.
Don’t try the setup as it works now, since the grinding noise and heat building indicate a serious problem and can easily burn out your motor.
If you have located the problem and the machine runs smooth again you can inforce the clamp on the motor with a bit of locktite. (Since you remove the motor the clamp part will wear a bit and there is a chance that it doesn’t clamp tight enough after refitting.)
The symptoms sound like excessive vertical play in the motor shaft. You say you replaced the bearing plate and bearing. I assume you mean the brush plate and bushing assembly. There should also be a thrust washer (or collar -P/N 600-129) that rests between the brush plate and armature. There should also be a thrust bearing ball (PN 600-110) that rests in the shaft bushing in the truck frame that is known to fall out unoticed. Did you check for that? If those are fine, sometimes you can stack more than one thrust washer to prevent excessive vertical movement. Especially if you replaced the brush plate. The easy thing to do is with the shell removed, cycle the engine forward and reverse and study the movement of the shaft end in the brush plate bushing.
Engines of this type often have two methods of thrust control. The thrust collar that goes between armature and brush plate and a ball bearing, part no. 600-110, that sits in the plate under the power truck… Generally if all electrical is okay your problem is with thrust.
Hello Jerry ! The Problem with those Motors was usually the Bottom plate would come loose causing the Armature shaft to have too much play and jam the worm gear causing erratic performance in both forward and reverse.The side frames were made of Aluminam and were not always stacked together properly resulting in a poor running Motor. If you can Call Jim Barret of Davis Trains he can probably guide you step by step in the process of getting this bum motor to run right again. Good Luck.
You need to tear down the motor truck and restake all joints in the aluminum plates so that everything is solid and square. It is also possible that the axle drive gear has become worn because of the misalignment. If so, it will need to be replaced.
I repaired one of these in this way a couple of years ago and it ran very well afterwards. In my case I didn’t need a new gear, but I did have to add shim washers at the top of the armature shaft to cut the vertical movement of the shaft to a minimum.
My current strategy for dealing with this problem is to avoid the later Alcos and switchers entirely. The ones made from 1949 to 1954 are excellent runners and give few, if any, problems.