Is there a standard tolerance for cooling tower fans? Lengths are from 75" to 120" span for drive shaft. Speed approx. 1165 rpm. Thanks!
(Just purchased a Rotalign Ultra and still green at it.Having a hard time getting it close.)

Alignment of cooling tower gear boxes with motor having a floating drive shaft is difficult with laser alignment kit. It is difficult to adjust as the span is too long.

Its easy to check radial & axial alignment by rim and face method by mounting dial guage at both ends.

Alignment can be performed easily and much more precise using your Rotalign Ultra. An easy way is to perform a 2 step alignment. set up your machine as a 3 machine unit. The middle machine is simply imaginary. Once you have results from both coupling simply align the Motor and gearbox to each other and just ignore any values from the middle machine. The Ultra has a neat feature where you can change around the Fixed Feet, which is a very powerful feature when aligning cooling towers.