Determination of Balancing Speed for Flexible Body

[connectionman]

Hello All,

Recently I have been searching how to determine the balancing speed of flexible body. Let me give an example;

There is flexible assembly which normally operates at 28.000 rpm. Until that speed, there is no critical mode. The nearest critical mode is around 33.000 rpm. Normally assembly was balanced at 2500-3000 rpm (Around G2.5 according to ISO 21940) However when used on the platform with this balance condition, it causes much more than force on bearing with respect to the calculated force on bearing.

Does anyone has any idea how to determine balancing speed for flexible body.

Thank you.

 

[connectionman]

@Tmoose unfortunately I can not provide that document because of company confidentiality.

@electricpete Balance process is already done with the method you suggested. However, this method is quite expensive and time consuming, because there are not enough sensors on the platform, we have to do it by applying "four run balance" method. That's why I would like to figure it out on detail assembly process.

 

[Tmoose]

Can you provide the name of the document or source that said -
"Moreover when we search on benchmark studies we have a same assembly concept but they balance their assembly at 7krpm. "

Have you also determined your "flexible assembly" uses the "same "assembly concept" ?

How many balance correction planes does your rotor offer, and where along the rotor are they?
Are there correction planes available in the middle 25% of the rotor?
A picture is required here.

Are there seal surface diameters or other features around the middle 50% of the rotor with radial clearances that will be compromised when the rotor bows due to significant "heavy spots" and develops mechanical runout over .006" TIR?

is the slow speed balancing being done in a "soft bearing (or "hard bearing" balance machine " ?

Is this a first of a kind product or installation?