Why is it necessary to loosen the motor set screws first when aligning a centrifugal pump with a laser?
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What is the reason? What else is the soft-foot phenomenon?
Was the motor’s four foot screws loosened before using the set screw? The main function of the set screw is to be used with the motor during centering ； The original purpose of the screw on top was to prevent alignment errors caused by the screw pressing against the motor feet. The soft footing means that the alignment values are within the normal range before the motor foot screws are tightened ； After tightening the anchor screws, the data is out of range. . . . It is likely that the gasket is not properly seated, the base of the motor feet is uneven, or the foundation base is uneven
Agree with what was said above – the set screws are used merely to facilitate moving the motor back and forth, left and right; in other words, they are used for alignment. When no adjustment is needed, they are in a loose state
It is to ensure that the data measured under normal conditions of the motor are accurate; if any external force is applied, the data will be inaccurate.
This post was last edited by Bai Yunfan on 2015-6-23 04:16. For aligning rotating equipment, it is generally required to first position the pump, then align the gearbox (if any), and finally the drive unit. In other words, during alignment, it is necessary to first specify the pump, and then adjust the position of the motor (by using set screws to adjust and fix its position) in order to ensure the final alignment accuracy. Soft feet mean that the four feet are not on the same plane as the tabletop. For the measurement of soft feet, one of the four foot bolts is usually loosened to check for any changes in alignment ； Then do the other three, and send away the remaining one ； Check sequentially to ensure there are no soft feet.
The set screw is used for static adjustment; once the desired position is reached, it is loosened. The characteristic of soft feet is that when all four foot motors are activated simultaneously, the vibration becomes severe; once the soft foot is released, everything returns to normal. This can be addressed by adjusting the shims or increasing the stiffness of the feet
The set screws of the motor footings can affect the accuracy of the laser alignment device; it is best to measure the motor feet using a dial indicator and an indicator stand. First, tighten the 4 feet, then loosen one of them; if the radial variation exceeds 0.08 mm, it indicates that the motor has a weak foot
The motor adjustment set screw is used to add or remove shims in the vertical direction and to move it in the horizontal direction. Once adjusted, all set screws need to be loosened. Prevent soft feet from forming. This causes the vibration to exceed the specified levels.