Just installed a used motor I was given in a Athearn RTR SD 50. While the engine was apart I tested the trucks and they roll easily and there was no biding.
When I tested the motor it made a lot of racket at slower speeds. But I have no idea when the last time it was ran. Oiled the bearings and went to test the amp's the motor pulled and started getting odd readings again from my (I now know it is junk) meter. When Simon was over we tested the motor and it read good. So I went a head with the install and deiced to pick up a new meter before I installed a decoder.
Picked up the meter and tested the motor in the chassis with all drive gear hooked up. While holding the engine on the test track at full speed it was pulling .60 amps, when stalled it pulled .85 amps. Ran it for a hour or so with out the shell and it seemed to quite down some.
Soon as I installed the shell the sound was much louder, because of the shell acting as a sound board. Went a head and speed matched it hopping it would quite down more. It has not.
Sound has a rasping quality to it and while out of the engine it sounded like it was coming from the commuter? (where the brushes make contact) And the brushes. While I am not ruling out bearings the sound does not sound like other bad bearings I have had go bad. Engine is quieter at higher speeds.
I did oil the bearings one last time before I started running the engine. Should there be in lube used where the brushes ride?
Thanks for the coming help.
Ken
I hate Rust
How is the motor mounted to the frame? The vibration from the universals is being transmitted to the frame and then the shell. The old super power Athearns were always noisy. My old SD9 with the Ernst super gears in the trucks does not need a sound decoder to sound like a diesel.
Try to remount the motor in a bed of RTV and see if it quiets down.
Pete
I pray every day I break even, Cause I can really use the money!
I started with nothing and still have most of it left!
Dirty brushes, or a brush that got turned around, or maybe the commutator segments need some cleaning. The difference between free run and stall amps seems too small. Maybe the brushes are totally work, if it's a used motor. If you look at the brushes, they are rounded int he direction of the commutator, but if the clips come off and the brushes lift up or are removed, they can come down with essentially just two tips touching the commutator - this will not run well and be noisy.
Since you mess around with so many Blue Box locos, you probably already know about the AThearn motor tune-up guide. http://www.mcor-nmra.org/Publications/Articles/Athearn_TuneUp.html#MOTORTUNING
Using this information a Blue Box loco can be made to run as good as many that cost much more.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
Thanks folks. I have that link but have not looked at it for some time. This is the first I have messed with Athearn's in sometime.
Randy, when you said "Maybe the brushes are totally work", guess you mean bad correct? Will check to see if my LHS happens to have some.
What should be the spread on running and stall amp's be? It seemed to run well, I had to lower CV 5 to around 210 to match the engines I was speed matching it to.
I had planned on polishing the commutator with 1500 grit paper and I will look at the brushes at the same time.
Pete Motor mount is the screw type and I am using the Hex Head Flywheels and drive shaft.
Thanks for the answers.
Try double sided foam tape between the motor and the screw mount.
Staples has some $3.99/package. I think Walmart carries it too
http://www.staples.com/Scotch-Double-Sided-Mounting-Tape-1-2-x-75-Roll/product_130450?cid=PS:SBD:GS:E:N:PLA:71000000000227334:58000000007550080:130450
Don - Specializing in layout DC->DCC conversions
Modeling C&O transition era and steel industries There's Nothing Like Big Steam!
Don, thanks for the idea. Motor was making the same noise when I was holding it in my hand so it not a lose mount. But may well cut down on noise transfer.
Well got another re powered. This one is a Rio Grand SD-50, motor is pretty quiet. In the chassis holding it in places it pulled .49 amps, stall was .95 amp. Should be ready to go!
I think you mean quiet.
Rich
If you ever fall over in public, pick yourself up and say “sorry it’s been a while since I inhabited a body.” And just walk away.
Yes I did Rich.