Gentlemen, I need advice regarding the issue of the high-pressure pump motor shaft being misaligned

The axial movement of the high-pressure pump motor shaft can be caused by the following reasons: 1. Bearing wear or improper installation: Check whether the bearings are loose or worn; if necessary, replace or reinstall them. 2. Coupler issue: Check whether the coupler is properly installed and aligned; imbalance or improper installation of the coupler can lead to shaft play. 3. Eccentricity or imbalance in the motor or pump itself: Ensure that the motor and pump are installed horizontally, and adjust their position to ensure smooth operation. It is recommended to carry out inspections and repairs from the above three aspects. If the problem persists, it is recommended to have a professional technician conduct further inspection and repair. .

Did the motor shift before the pump was sent back to the factory? If there is no shifting, I personally recommend checking the coaxiality first; the photos show that there is also a gearbox in the middle. If the motor shifts despite the coaxiality meeting the requirements, then it’s necessary to check the pump.

Check the magnetic center line of the motor

The reason for returning it to the factory was the high temperature of the motor bearings. I didn’t explain it clearly before – it was the motor that was sent back to the factory, not the pump. As for coaxiality, since the pump body hadn’t been moved, I didn’t consider the issue of coaxiality. Moreover, given such a large deviation, the normal bearing temperature is also a point of confusion

Could you explain it in more detail? I’m not very familiar with motor knowledge

And looking at the pump, this pump is equipped with displacement monitoring; the displacement data hasn’t changed. I still think the issue lies on the motor side

Introduction to the magnetic center line of electric motors _ Rotor _ Requirements _ Restrictions

Of course, the person who touched it is the most suspected; if the motor was touched, then the motor should be the focus of the investigation. But first, it’s possible to check and rule out issues related to coaxiality.

This post was last edited by Spicy hot pot_rqMms on 2025-4-17 08:26. Some updates regarding pumps: I obtained the backend data yesterday. Guys, please help analyze it (at the end of the main post). It can be seen that the pump coupling end shows an upward trend over a period of time, after which it stabilizes, with the displacement waveform changing accordingly. The problem now is to go back and look at it in person: if such a level of displacement were caused by a pump, the magnitude of the displacement should not be so small. Moreover, the video recording continued without interruption, as there was no termination due to stable data conditions. The bearing temperature has remained unchanged. My current problem is that I’m not familiar with the internal structure of the motor, so I’m unable to analyze it or make any judgments. I hope everyone with relevant knowledge will share their insights; thank you.

This post was last edited by Spicy hot pot_rqMms on 2025-4-17 08:44. Thank you for your reply; my understanding is that this is a distance requirement, and even if it isn’t met, why does it still cause axial movement back and forth? I don’t understand. I’m sorry; I just realized that the image contains a link. I read the article, and it mentions that when the motor is operated alone, issues such as misalignment of the magnetic center line can occur, leading to interference signals. What happens then when a load is applied? Does the offset disappear even if the centerline is not aligned, thanks to the stresses exerted by the rotor and coupling? Or in other words, I can only remove the coupling and test the motor separately; if misalignment still exists, it can be confirmed that it’s a problem with the magnetic center line? And doesn’t this situation cause changes in the temperature of the electric bearing?