Whistle Tender motor clatter

[Fordiesel69]

http://www.youtube.com/watch?v=gbWbuxxoEdM

 Not sure if this guy is a member here, but I stumbled across it and found it intersting.  Is this normal for the motor to clatter like this, or is the armature bad?  I was thinking at first the commutator could be off a few degrees or quite possible the gaps are enlarged and therefor the brushes catch.  Ideas?

[mdainsd]

Thats what they sound like. Remember the tender shell is off. You dont hear the clatter as much with the shell on. Also higher track voltage helps.

[cwburfle]

Fordiesel69

Not sure if this guy is a member here, but I stumbled across it and found it intersting.  Is this normal for the motor to clatter like this, or is the armature bad?  I was thinking at first the commutator could be off a few degrees or quite possible the gaps are enlarged and therefor the brushes catch.  Ideas

That one is rather noisy. I;d check the tension on the brush springs. If the spring tension was OK, I might try replacing the brushplate to see if the noise goes away. . There isn't any bearing in the brushplate, after all these years, the hole might be enlarged, especally if the motor wasn''t kept properly lubricated.

[Fordiesel69]

I also detect a slight sound on spin down like something is draging on the commutator face or possibly the armature is rubbing the field.  I hope they were not built that cheesy to sound like that. 

[servoguy]

 Let me say that based on my experience, this is pretty much normal for whistle motors.  Notice that the noise is louder when the motor is powered than it is when the power is turned off. 

I believe the noise is coming primarily from the torque ripple of the motor.  The 3 pole motors that are used in Lionel whistles and engines have a lot of torque ripple.  This torque ripple will show up as mechanical noise.  You can hear it from a motor in an engine, but it is not as loud as a whistle motor because the weight of the engine tends to damp it. 

Recently, I was testing a whistle motor, and as I varied the voltage, I could hear the torque ripple beating with the 120 Hz torque ripple that comes from the 60 Hz power.  My conclusion is that this noise is inherent in the design, and not much can be done to eliminate it.

[servoguy]

 One more thought:  Loose bearings may cause additional noise as the shaft rattles in the bearing due to the alternating magnetic force on the armature. 

Some of the bearings on whistle motors are very hard to lubricate.  The one on the brush plate is easy, the other one is difficult.  On two motors I lubed recently, I put a drop of oil as close as I could get it to the bearing, and then washed the lube into the bearing with WD-40.  This has worked OK so far.