How to install and balance flywheels on motor?

[es80ac]

Hello.  Does anyone have any word of advise on how to install/secure flywheels on a replacement motor and how to properly balance the flywheels/motor set up?   Thanks

[Deleted]

Sept 12, 2019 20:45:39 GMT -8 es80ac said:

Hello.  Does anyone have any word of advise on how to install/secure flywheels on a replacement motor and how to properly balance the flywheels/motor set up?   Thanks

I have never had to balance a flywheel.

To install one, I use a drill press and some spacers to press the flywheel onto the motor shaft. I make the spacers from thick styrene sheet.

Brian

[edwardsutorik]

If you wish to balance the flywheels, do it before you install them:


Press one of the flywheels onto a temporary shaft (NOT one on each end of the shaft)
Place the shaft on a fixture made of two razor blades--the blades should be pointing "up", and have the cutting edges parallel and level
If the flywheel rolls on its own to a stop, mark the high point with a sharpy and do it several more times. If the marks are all together, that's the light side of the flywheel
If the flywheel needs balancing, the heavy side will consistently appear downwards--drill a hole and try again
The hole is usually best drilled midpoint between the two outer faces

Possible problems:
you didn't make the temporary shaft long enough, and the flywheel end keeps flopping off the blades
you didn't do a good job of making the fixture "square and level"
you've damaged the blade edges enough that they aren't good bearings anymore, and must be replaced




Ed

[es80ac]

Thanks alot folks for your answer. Do you know how the manufacturers fit/balance the flywheels onto the motors at the factory?  I see most factory installed flywheels are quiet perfectly balanced, you don't see any inkling of wobble when the motor is turning.   Is it because the holes they have drilled are perfect or if there is an additional step at the factory to fine tune the flywheel fit?  

[edwardsutorik]

Sept 13, 2019 8:35:28 GMT -8 es80ac said:

Thanks alot folks for your answer. Do you know how the manufacturers fit/balance the flywheels onto the motors at the factory? 

No.

I see most factory installed flywheels are quiet perfectly balanced, you don't see any inkling of wobble when the motor is turning.   

I would say you are finding that they are ADEQUATELY balanced. They quite likely could be balanced even better, but the rewards (as you have noted) would be minimal.

Is it because the holes they have drilled are perfect or if there is an additional step at the factory to fine tune the flywheel fit?  

It is possible to assess balance of the whole motor/flywheel assembly, using a special machine. I used such a machine a very long time ago to balance rotational equipment. They may use one, or they may have other approaches. My use of the term "special machine" should indicate that few model railroaders would consider actually buying one. But, using such a machine, one can do quite a nice job of balancing the entire assembly, as a unit. As opposed to flywheel-motor-flywheel. And it will likely cover dynamic balancing, in addition to the more common static.



If you have an existing installation, and you don't find any objectionable vibration, there would appear no need to go further. The more balanced the rotation, the less wear on bearings and the less irritating vibration.

If you are doing a fresh assembly, there is no downside to balancing the flywheels. IF you do a good job. Of course, they may not NEED to be balanced. You'll find that out to. IF you do a good job.


Ed

[es80ac]

Thanks Ed! I sure learned alot, appreciate it!

[NS4122]

I've noticed that on my Intermountain GEVOs and Tier 4's the flywheels have sharpie marks and some blue stuff in the groove 90 degrees or so off the black mark, so they must have a need to balance them. The motors with flywheels are refered to when buying replacements as NWSL motors.

[edwardsutorik]

Yeah, you can add or subtract weight for balancing. For flywheels, I would go with "subtract", because:

you won't be adding to the outer circumference, and risking scraping something

your modification can't come loose


Ed

[NS4122]

Sept 13, 2019 12:01:55 GMT -8 edwardsutorik said:

Yeah, you can add or subtract weight for balancing. For flywheels, I would go with "subtract", because:

you won't be adding to the outer circumference, and risking scraping something

your modification can't come loose


Ed

Not a problem with the NWSL motor flywheels as they have a groove cut around the flywheel ends that holds the weight flush.