Hi,
I have run into an electric motor that needs to be balanced, but has nowhere weights can be attached...

What is to be done in such a situation?

My first thought was to fabricate and install two balancing disks on each side of the motor with holes drilled at every 15 degree increment.

Any thoughts or experiences?

Thanks

Does the motor have a cooling fan? Weights can be added there if necessary. How about adding weights at the coupling?

What size is the motor and what kind of rotor does it have?
Small rotors are typically balanced by drilling out material from the iron laminations close to each end. Care has to be taken not to short the laminations.
Largr rotors can be balanced by adding weight to the ens rings or, with a wound rotor, by adding "heavy" epoxy putty inside the windings.
Most rotors have shorting rings at each end which can also be used to attach balance weights or for metal removal.
The key here is what kind of rotor do you have?

Every motor I've seen wiggle (and needed correction), moved in the direction of the key at the coupling. I've cut the key down and reduced the vibration.

Be careful when running motors alone, if they are balanced according to standards they should be balanced with half key and that works when attached to another thingy that also is balanced with half key. This is not always the case in either end and may give some need for fieldbalancing luckily. I have a sticker on my hardhat that says "Balanced with half key". Go figure, it´s Friday. Olov

ISO 8821 addresses the key fitment issue rather well, but ISO was at the source of some of the problems with keys. The U.S. used the half key convention for the most part throughout, but ISO had a full key and no key convention for balancing.

Some countries switched from their own half key convention to use ISO (other countries may have been using a full key convention anyway) when it was using the other convention (described somewhat in the standard to help eliminate problems in the future). Machinery balanced in these places at the wrong time still give rise to problems today.

ISO re-evaluated the proceedure, and we have what we have now, workable proceedures.

Bill,

Can you tell us what that "workable proceedure" is in ISO 8821?

Thanks,
John J