We received a service request for a high vibration problem on a Micro Pulverizer motor. The customer specifically reported abnormal vibration in the axial direction on both the DE and NDE sides. Our team visited the site and began by collecting complete vibration data from all measurement points.

During the analysis, we identified that the motor DE side axial vibration was significantly high, reaching 6.38 mm/sec RMS, with a strong 1X running speed peak in the spectrum. This type of signature normally indicates a possible unbalance or alignment-related issue, but we continued our investigation to confirm the exact cause.

As part of the troubleshooting process, we checked the machine for mechanical looseness, structural looseness, and dynamic soft foot conditions. All these checks showed normal results, with no symptoms indicating looseness or soft foot. Since the initial checks didn’t reveal the cause, we decided to run the motor in solo condition (uncoupled).

During the solo run, the vibration level in the DE axial direction increased further, reaching 8 mm/sec RMS. This rise in vibration during solo operation indicated that the issue was coming from the motor itself and was not related to the pulverizer. The pattern of vibration and the spectrum indicated a static unbalance condition.

After confirming this, we re-coupled the motor with the pulverizer and proceeded to perform field in-situ balancing on the motor coupling side. We added calculated washers as correction weight. After applying the correction, we observed a significant improvement: the 1X amplitude reduced from 6.27 mm/sec to 2.98 mm/sec in the axial direction. The machine operated smoothly after balancing, and the customer was fully satisfied with the outcome.

The main takeaway from this case is that unbalance is not limited to the radial direction. It can occur in any direction including axial direction and must be diagnosed carefully using vibration data and proper testing methods.

For professional vibration analysis, in-situ balancing, and rotating equipment troubleshooting, please contact info@rasetechservices.com