06/02/2026
Machine Train Shaft Alignment - Saudi Arabia
Client: The client was an electrical submersible pump (ESP) manufacturer for oil wells located in Saudi Arabia.
Equipment Measured:
The machine train consisted of an electric motor connected to one end of a torque cell. The other end of the torque cell was connected to the thrust chamber (refer to Figure 1).
The electric motor was manufactured by Marathon Electric and had a power rating of 260 kW operating at 3,570 RPM.
The torque cell was manufactured by Honeywell and had a torque rating of 5,000 in-lbs and an operating speed of 22,000 RPM.
The thrust chamber was an in-house design.
Problem:
The original torque cell was damaged due to vibration and was subsequently replaced with a new torque cell. However, the machine train continued to experience severe vibration issues, which had become the leading cause of downtime and component replacement.
After installing the new torque cell, the client's alignment team performed shaft alignment, but the vibration problem persisted and acceptable alignment results could not be achieved.
This machine train is used to test electrical submersible pumps (ESPs) for oil wells. The pumps must successfully pass quality assurance testing on the machine train before shipment to end users.
The client needed to restore the machine train to full operation as quickly as possible because several pumps were awaiting testing. Any further delays had to be avoided, as no backup equipment was available.
Solution:
As-found alignment readings were recorded between the thrust chamber and the torque cell. The alignment setup is shown in Figure 2.
Additional as-found readings were then taken between the torque cell and the motor. The results indicated that the torque cell was misaligned relative to the thrust chamber, and the motor was also misaligned relative to the torque cell.
Alignment corrections were performed on the torque cell. During this process, it was observed that the torque cell base was weak and unstable. This instability significantly affected both the alignment readings and the correction process. Furthermore, the unstable base increased the likelihood of alignment drift over a short period of time, resulting in recurring misalignment issues.
Conclusion:
The original torque cell base was weak and unstable, causing vibration and misalignment during operation. Over time, this instability adversely affected other machine train components, including the couplings and bearings, as evidenced during the alignment inspection.
The coupling exhibited a runout of ±2 mils, and excessive bearing clearance contributed further to the vibration problems.
Additionally, all motor feet were found to be bent due to improper alignment practices that attempted to compensate for the instability of the torque cell base. Poor shimming practices were also observed, including the use of washers as shims and excessive shim stacking to achieve the required height.
