This second part of rim and face shaft alignment will make you understand why we can add radial alignment and angular alignment correction together and angular alignment correction makes no change in radial position . Also you will understand why in some cases why you are adding shims while the motor is up .At this moment alignment technician or engineer become confused why the result (calculation) is coming like this. The answer is angular misalignment correction shims required to be added are more than the amount of shims required to be removed . For example motor is up by .1 mm . So radial correction is minus 1 mm from front and back support . At the same time angular misalignment correction is plus .2 mm front side and plus .4 mm back side . So net addition will be - .1mm + .2mm =+.1mm front side and for back side it will be -- .1 mm +.4 mm = . 3 mm back side. So net result is we are adding shims althought motor is up .In short result is plus because of angular correction .But front side and back side shims are not same.