We are having two Motor mounted single impeller centrifugal fans. Generally only one out of two is running.
These fans are sharing same frame and hence when both fans are running we experience beating phenomenon.
During our schedule monitoring we found high vibration in a fan 'A'. Diagnosis revealed balancing problem. Now the problem is that to balance the fan it is required to be run along with fan 'B'. But, when both fan are running amplitude on 'A' varies from 4 mm/sec to 18 mm/sec.
Can anyone suggest how to proceed for balancing