about the alignment of shafts between driver and driven machine

opening – is this the gap at the opening?

The overall misalignment is determined by subtracting the A gauge value from the B gauge value and then dividing the result by 2. This calculation eliminates the effect caused by the movement of shaft a*, thereby indicating the degree of opening between the flanges. A negative value indicates that the flanges are more open compared to their opposite position. How should the red text be interpreted? There is parallel offset among misalignments, where the centerline of the motor shaft and the centerline of the pump shaft are parallel but not on the same straight line; the distance between them is the offset. There is also angular misalignment, as well as a combination of both. This passage describes the alignment using a double-table coupling; it means that the axial misalignment value is obtained by taking the difference between the readings on Table A and those on Table B, and then dividing that difference by 2 (i.e., the so-called TIR). This calculation eliminates the effects of axial movement and reflects the gap between the two flange surfaces (i.e., the two halves of the coupling). A negative value indicates that the two flange faces are opening in opposite directions to a greater extent. :Q

The axial misalignment is determined by subtracting the value indicated by gauge A from the value indicated by gauge B, and then dividing the result by 2. This calculation eliminates the additional amount resulting from the axial movement of the shaft, and it shows the degree of separation between the flanges. A negative value indicates that the flanges are further apart than in the opposite position. The axial misalignment value is obtained by taking the difference between the readings on gauge A and gauge B, dividing that difference by 2; this result removes the effect of axial movement and reflects the extent to which the two flange surfaces (i.e., the two half-couplings) are separated from each other. A negative value indicates that the two flanges are opening further in opposite directions. The flange should be in an open-angle position, not an open degree, that’s my personal understanding. . .

I’m here to provide more context for cross reference: Starting from a position where the misalignment value is zero, it means that the flanges are closer together at position 3, with a value of +0.04 (position 3 is opposite to the starting position). Compared to the starting position where the misalignment value is 0, at position 3 with a misalignment value of +0.04, the flanges are even closer together (position 3 being opposite to the starting position).

Generally, the entire surface is divided into four points, just like on a clock: the 12 o’clock position, the 3 o’clock position, the 6 o’clock position, and the 9 o’clock position. Zero the instrument before measurement; the value at position 3 in the text should be the one measured at the 6 o’clock position at the bottom. :lol