Centrifugal Blower-Direct Drive Base - rigid or spring mounted?

[Kaplin]

We are in the process of replacing our belt drive with a direct drive on a 30000cfm centrifugal fan. The existing fan/motor base is mounted on a number of springs (design would be circa 1970).

Is it still common practice to mount these type of systems on springs, vs rigidly mounting them to the base? We have experienced signs that the base above the springs is not stiff enough and has been twisting - causing misalignement of the fan and motor. The options I see are to either remove the springs and rigidly mount the base, or increase the stiffness of the existing base above the springs.

Thoughts?

 

[imok2]

Google this and talk to these people:
Centrifugal Fan Isolation Base Assembly Instructions

 

[willard3]

If you have building noise problems with this machine and it is mounted above the basement, fix the base and get new springs.

If you are in an industrial place and noise is not a problem, take out the springs and mount it rigid.

 

[Drazen]

adequate cluch should enable some alignement tolerance.

you need not only the springs, but also the structural noise isolation beneath the springs.

the biggest issue is weight balance of fan and motor base. if you are going to change the type of drive that could be critical issue.

i am curious how come that drive manufacturer has no any retrofit guidlines?!