Help with 2046W tender whistle problem

Larry, I would check the amount of up and down play in the armature, it should only be a slight amount. New brushes and especially new springs might help, as would a liberal oiling of the bushing at the bottom of the armatures. The relay should have a good cleaning of the contact points, and the gap should be carefully adjusted to about .040 to .050 of an inch. If the gap is too great it will not pull the motor on quickly enough. Also, clean wheels and clean rollers are necessary. I am sure there will be other helpful ideas posted, but this is a start. 

It sounds like the motor needs a good oiling. You definitely need a needle oiler to oil the bottom armature bearing. The brushes should be replaced if they are worn.The top of the armature shaft where it comes through the brushplate needs to be oiled also.

Larry

Thank you, Luke.

The up and down play of the armature(and thanks for the correct nomenclature) is less than 1/16th of an inch. The contact points open and close right on cue in conjunction with the motor start and stop. Wheels and rollers are very clean. The brush spring tension is an interesting notion. I may try giving each the slightest pull to increase tension before I start a search for new springs. 

I may try oiling the bottom bushing, but it would be done blind as the impeller for the whistle is attached to the bottom post and the bushing is not visible as far as I can tell. I'll give it a shot, though.

Thanks again for the help, I really appreciate it.

Larry

Thanks Larry. I do plan to use a needle oiler for the bottom bearing. The brushes don't appear to be excessively worn as there is a good 3/8 of an inch or more remaining. If I oil the top shaft, and I would only use a drop, could any excess make it's way onto the armature and under the brushes interfering with a good contact surface?

Thanks again,

Larry

If you use just a drop of oil on the top bearing, you should not have a problem with oil getting onto the brushes and commutator.

To get at the bottom bearing, you need to get that needle oiler inside the motor, between the armature windings, and down to the bottom bearing. Tricky, but can be done.

Larry

Remove the studs that hold the motor assembly to the sound box. Remove the motor assembly. Look for scuffing in the hole where the impeller goes. If you see any scuffing at all, you need to press the impeller onto the armature farther. This is typically the cause of growling and over heating with these units. 

Gandy.

Thanks Gandy and TrainsRMe for the ideas. However, after oiling, eyeballing clearances and taking the motor free from the sound box, the noise remains. When I removed the motor from the sound box, I powered up the transformer and pressed the whistle button. With the motor now running and free of the sound box, the noise was somewhat diminished but still audible. The growl noise seemed to be coming from from one side and low on the motor. Also, the brush housings continued to get really hot even though the motor was now clear of any possible binding due to being housed in the sound box.

Additionally, I'm not completely positive what the whistle should sound like and what other noises go along with blowing the whistle. I believe the motor could not possibly be as quiet as say a modern can motor, but the noises and overheating problems aren't normal either.

Even though the relay bracket seems solid enough, I'll try Gandy's suggestion because I can't eyeball a grounding issue unless, of course, it's sparking.

I don't know folks, seems to me I have a real poser here.

But, believe me, I most certainly appreciate all of the ideas I'm getting.

Thanks a million,

Larry 

Larry, it's quite possible that the motor had been run 'dry'.  This will cause a glaze to form on the fibre brushplate where the armature goes up thru it.  Oil (lube) will not soak into the glazed area.

I use a small round file and rough up (not enlarge) the hole.  I also lightly sand the armature where it makes contact with the brushplate.  I then oil the hole and follow that with a good lubriplate type grease once the brushplate and armature are assembled.  I've done this type of repair many times on fibre brushplates.  It has worked for me.

There is a possibility that one or both motor bearings may be worn. Grab the impeller at the bottom of the motor and try pushing the armature side to side (not up and down). There should be no play. Same thing with the top of the armature shaft coming through the brushplate. Try and wiggle it. Now power up the motor and watch the top of the armature shaft. It should spin dead true. If you observe any wobble to the shaft, the brushplate needs replacing.

Does the motor spark excessively when spinning? If so, clean the commutator again, and use a toothpick to clean any gunk in the slots separating the commutator segements, and clean again. If it still sparks excessively, then you may have a slightly shorted armature.

Larry

Thanks Johnsgg1. I'll give your suggestion a shot, because while I had the motor running and disconnected from the sound box, I noticed the brushes giving off sparks.

I didn't think much about it at the time, but a glazed armature surface would make for a lousy contact surface and therefore spark and overheat.

Thanks again,

Larry

Larry,

Thanks for the great advice. I'll check it out and see what I can find.

Larry 

Larry, you misunderstood.  Although the armature surface/commutator should be clean and glaze free, I was talking about the small hole in the fibre brushlate that the armature shaft goes through.  There should be no glaze on the walls of that hole.

For your heat and sparking problem I suggest getting new brushes and springs.

Reclean the commutator plate before installing them, and clean the brush tubes. I took up on a suggestion I read here to burnish the insides of the brush tubes (holders) with a brass gun barrel cleaning brush. I think they work well.

I am suggesting the brush replacement because I have found that once a brush gets oil on it, the oil seems to soak into the brush, and no amount of cleaning will get it out.

Many thanks to the Train Doctor, TrainLarry, The Gandy Dancer, TrainsRMe, Johnsgg1 and C W Burfle for all of their help and suggestions.

After all is said and done, it looks like I'm dealing some substantial side-to-side wobble in the armature shaft. And thanks to all of you my next step will be to find replacement parts and go from there.

Thanks again folks,

Larry

Can anyone say what the clearance should be on a new motor bushing?  I have a reamer that is 0.1253", but sone times I think it is too tight. Without knowing the tolerance on the shaft, it is hard to get the bushing bore correct.

David,

  You would want to start with a reamer .0005" over the shaft size for a clearance fit, but not more than .001" oversize, or the shaft may start to wobble.

Larry