When aligning a horizontally split centrifugal pump after maintenance, is it necessary to consider the magnetic field lines for the sliding bearing motor? Is there any standard to guide this?
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The problem is as stated in the title. We produce horizontal split-case pipeline pumps, mainly of the BB1 and BB3 types for oil transfer (with motor power ranging from 355 to 2100 KW). For motors with sliding bearings, after major repairs to the pump, the motor is first tested under no-load conditions to determine the position of the magnetic field lines, which are then marked. The motor shaft is subsequently aligned with these marked lines to check whether the installation distance between the couplings is appropriate. The question is: since the position of the magnetic flux lines is marked on the motor at the time it leaves the factory, can this marked position be used directly as the location of the magnetic flux lines? Why is it necessary to test the motor under no-load conditions to determine the position of the magnetic flux lines? Are there any standards that require this approach? Today, when my supervisor asked me about the relevant standard (as he thought it was possible to skip the step of determining the magnetic flux line positions under no-load conditions), I really couldn’t say which standard specifies this. :(
The most favorable criterion is the value of the \"distance from the magnetic centering line\" provided by the manufacturer. If there are any problems, turn to the manufacturer; you can consult them now or ask them to send a letter to confirm things. Magnetic alignment is not absolute either; it represents a boundary that ranges from strongest to weakest to strongest again.
There is no need to find the magnetic center line every time; without moving the motor, the magnetic center line generally remains unchanged. If you disassembled the motor, you still need to look for it. Prevent the bearing from being subjected to axial tension. If the leader doesn’t understand, there’s nothing but to laugh.
After the motor is overhauled, it should be checked to prevent the bearings from being damaged by axial forces.
I can only say that your leader must have had a good education, but doesn’t understand what goes on on the ground. For maintenance personnel, they do things in the most reliable way possible, as no one can guarantee that what the manufacturer provides is accurate. It’s also not easy to measure. Anyway, we confirm the magnetic field lines after conducting dummy tests. Reliable
There’s one on the sixth floor. Doing this gives me confidence