DC Can Motor Question

I assume the can motor is brushless.  When you lubed the engine, did you pull the motor? Could have been some dried up grease in the gearbox.

Gilly

I did pull the motor.  There was plenty of grease and it looked fresh.  I did add some Red and Tacky #2.  Everything looked fine in the gearbox.

Earl

None of the can motors I have seen for model train use are brushless.

Your symptom sounds like a speck of ballast in the spur gears.  Clean them, and go easy on the sticky grease.  The slowing down is one motor stopped and the other pulling it along.  Easy to burn up a motor that is dead- stopped.

Bob's theory sounds most likely. Earl does this engine have one or two motors? I know the early FAs had only one.

Pete

If this is a NOS unit, it could be that the brushes just needed to get seated as part of break-in after extended storage in new condition.

Earl, Your theory is probably correct.  I always remove the motor and rotate gears by hand.  If smooth and free, turn motor unattached by hand.  Then reassemble and rotate.  If still free, then the motor can be an issue.

Sounds like you ran off any varnish/corrosion.  Basing this on new but old stock.

Every once in a while you can run into a motor with a bad armature segment or winding.  It won't start when on that segment, but can run if started on a different segment.   G

The engine has only one motor.

i also fully expected to see some foreign material in the worm gear but I found nothing but fresh clean grease.  Additionally, I checked the wheels while the motor sounded like it was trying to run and they were all free to move a few degrees consistent with a worm gear mesh.  Additionally, the short buzzing sound I heard once when the engine was running very slow is more consistent of an electrical problem than a mechanical problem.

i smelled the motor and I could detect a very slight burning smell, but that may not smell abnormal as I have nothing to compare the smell to.  The motor was slightly warm to the touch, maybe 4 or 5 deg F above room temperature after a couple minutes of running.

i also originally suspected the reverse unit may have been feeding the engine AC and I was going to put a scope on it but after the engine started running, I assumed the power was OK.

The engine continues to run fine so I am still puzzled as to the cause.

Earl

If an engine is being stalled you will hear a buzz and possibly smell burning as the amps go up and the windings heat up.  G

The buzz was a one-time event that lasted less then a second and the engine light did not dim during the buzzing.  Additionally, I have 6-amp fast-acting breakers on every channel of the postwar ZW and they did not trip.

i have been starting and stopping the engine numerous times to see if I can find a bad armature segment and the engine performed flawlessly each time.  How many armature segments are in the motor?

Earl

Since that engine had been sitting around for a while it is possible for one or two things to happen, first the grease could get hard, second the capacitor in the circuit board might be failing from not being put to use for several years. If the capacitor goes out you need a new circuit board or somebody who knows a lot about repairing a circuit board.

Lee Fritz

With can motors, they either work well or they don't. If they don't work well you replace the motor and not repair it.

Lee Fritz

Sounds like the loco was pretty old. Was the chassis a natural silver metal color??? Those are early units. And all the can motors I have seen in O scale locos have brushes.....the only brush-less can motor I have seen are in some high end N scale locos. If it is running well after a little break-in  period.....blame some dirt corrosion in the motor! 

The chassis is black.

I think this is just going to be another event with an unknown cause that will, hopefully, not repeat.

Earl

Earl, They vary from 3 to 6 segments or poles.  The buzz could have been something burning out between brush and segment.

Sounds like it is running fine now.  G