Effect of the dial indicator installation position during alignment on the calculation formula
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In both diagrams, the motor is on the left and the pump on the right. The dial indicator is attached to the side of the pump’s coupling, opposite the motor. When the gauge used to measure axial alignment points toward the pump or toward the motor (as shown in the diagrams), does it make a difference whether S1-S3 or S3-S1 is used in the alignment formulas (Front shimming height Y1 = L1*(s1-s3)/D + (a1-a3)/2; Rear shimming height Y2 = (L1+L2)*(s1-s3)/D + (a1-a3)/2)? Sometimes I see in some introductions that the + sign in the formulas turns into a -, which confuses me a bit; I’d like to ask for advice.
If the axial gauge is set up as shown in the diagram, the two readings will be opposite to each other. That is, if the value on the left side is positive, then the value added to the right side will be negative.
The way in which the axial table is arranged affects the judgment regarding this, as well as the judgment concerning mouth opening; if the judgment is correct, it has no impact on alignment. If it is the lower opening, the reading on the upper axis gauge when it is rotated 180 degrees downward is positive, while the reading on the lower axis gauge when it is rotated 180 degrees downward is negative. It’s easy to understand once you think of the header pressure being positive.
If the axial gauge is set up as shown in the diagram, the two readings will be opposite to each other. That is, if the value on the left side is positive, then the value added to the right side will be negative
It has nothing to do with the radial direction and is related to the axial direction (that is, the opening); 1 indicates that the position with the larger number is where the opening lies. 2 indicates: the position where the larger number is located is there, and its opposite side is the opening.
During alignment, the dial indicator is used to measure the upper and lower values on the outer circle; as it moves from 0 degrees to 180 degrees, if the contact point of the indicator rod retracts, the pointer rotates clockwise. In this case, the reading should be recorded as a positive value, right? At this point, a1
Could you please take a look? Based on the measurement results, is this the correct way to draw a schematic diagram of the coupling position?