Dynamic v Couple Unbalance

[bassman1976]

If I know static imbalance in two different planes, I can calculate couple imbalance. Dynamic imbalance is the "combination" of couple and static imbalance. If I know static imbalance and couple imbalance, how do I calculate dynamic imbalance?

 

[Xwheelguy]

You speaking in terms of tires or wheels? And why not just take the wheels/tires to a service center & see if they will check the balance for you using the appropriate equipment to reduce the possibility of error?

Tim Flater
Senior Designer
Enkei America, Inc.

http://www.enkei.com

 

[bassman1976]

I'm speaking in terms of DC motor armatures. I just figured if anyone would know about balancing rotating machines, it would be wheel and tire guys.

 

[GregLocock]

You also need to know the cross coupled imbalance before you can work out the true state of affairs.

That is, you need three pieces of information

- the change in response (in phase and magnitude) at measuring plane 1 to a trial mass on plane A call it R1A

and

R2B

and

R2A or R1B, but preferably both









Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[Tmoose]

Do you need to resolve the "static" and "couple" already derived by some measuring method ( probably using Greg's method) into appropriate left and right plane corrections?

Add 'em up vectorically or graphically.
The couple is 2 equal and opposite imbalances separated by some distance. Choose that distance as your distance between correction planes.

Then break the "static" unbalance into 2 equal pieces, and add one to each end.