Noise and low speed operation

[Deland]

 I have 2 GP 40 Bachmanns. They both run about 9/28 well but are a bit noisy(lugging elect motor noise).At about 10-12/28 they quiten a lot and run well. They will run slower but eventually stall.
I also have a Walthers GP40 that will run all the way down to 1 and just barely crawl which I assume is normal. I'm just asking to be sure this is normal but since both Bachmanns do it and I know most claim they don't run slow as well as others, I'm assuming I'm right. My plan is to run the Bachmanns as a consist so slow speed op will be minimal so I don't see a problem for me with that.

[electrical whiz kid]

Noise in a motor is characteristic of induction.  This can vary muchly by many influences.  In your case, you failed to mention what type of motor it is making that noise?  Is it an older motor?  That kind of information is really needed in order to assess what may be the culprit.
Noise can be caused by things like:  lead/lag differences in voltage and current (AC), excessive internal resistances, mechanical issues like crud build up on the commutator, scarred stator, etc. 
DC motors are, essentially, series-wound motors, until you get into the much newer stuff, which I am not all that familiar with.
When approaching this problem; remember that, in the case of DCC; even though your track current is 14-18VAC, the decoder will rectify the motor current to DC.  I hope this helped you out a little-Oh, by the way;  If you want to hear noise, you ought to hear a 50HP three-phase motor "single-phasing" (lost one leg)... at 480 and up...

Rich C.

[jward]

if these came from the factory with dcc the noise id probably due to the decoder. replacing it with a silent running type will eliminate the noise.

if your locomotives are just starting to run at speed step 9 then you should probably adjust cv2 which controls the start voltage. try raising the value of cv2 by increments of 5 until your get the locomotive to run the way you want.

[Deland]

 Rich C. I'm familiar with a 3 phase motor single phasing, 35 years as a maintainence mechanic does that to a guy.

jward, I'll check that cv2. I don't need much sloowww running from it since it will be a mainline consist for the most part.

[brokenrail]

Hello,
Check the rear worm gear bearings/bushings to see of the gear case that holds it is strieght in relation with the back side of the worm gear. I have had a few that were bent back a little.This will cause the worm gear to wear on only half of the face of the bushing that acts like a thrust bearing also, and create more play in that area.Shimming it with a washer would do no good .If this is the case .It needs a gear case that is straight. They offer this replacement part, or a complete truck.This is a factory defect and will cause gear noise going down grade and a bind up at slow speeds in a certain direction. Would also act like a bad ring & pinion gear mesh in a differential since this is what it is.
Johnny

[Deland]

 OK, just for info so if others ask. I had run these locos for a while but evidently not long enough. I've run them a bit more on my test track and find that they are getting quieter and running smoother. Low speed has improved some but not as much as the other symptoms. I'll be running them more soon and when they quit improving, I will try jwards suggestion of playing with the cv a bit.