With many large conveyors it is not possible to carryout a laser alignment unless you lift the counter weight and pull the belt slack.
I have seen an attachment for Rotalign that allows you to laser align but you must take several measurements to get a good average.
Has anyone seen or made an attachment that allows you to rotate the reciever on the fixed coupling.

on the fixed machine, I would rotate the LASER using magnetic brackets. As long as the back of the coupling is flat. The bracket sits down on the shaft. I would use the pass method, only uncovering the receiver lens when I moved it passed the laser.
You could probably use multiple point, but it would be difficult unless the coupling was like new condition. Moving the laser is tough. But it can be done.

D

I used to un-coupled the gearbox output and align motor-gearbox by rotating both shafts. I then just perform manual alignment with a taper gauge on the output coupling. It is usually enough for those speeds.
Best regard, Marcel

You don't have to 'laser' align. There are many methods available. Fit the method to the job and use the best method.

We have one example with RSR 350 vertical pumps of M/s KSB, Germany make(2.8 MWe). The motor can not be rotated during alignment (weight around 22 tons). We have made rigid fixtures mounted on pump coupling with dial resting on motor coupling and rotate only the pump coupling during alignment. The motor coupling has been machined to high perfection (runout around 5 microns). there has never been any problem with these pumps and they run for almost 15 years or so without any overhauling. But in such cases of alignment the fixed coupling runout has to be very low for any meaningful alignmnet results.
Regards.

Sam, I probably have less alignment experience than nearly everybody here, but can imagine a lot of situations where various methods would be better than others. Maybe one possibility is to use an indicator to check the fixed shaft, then add an extension to the indicator and take another reading farther out on the same shaft.

In my shaft alignment kit, one such configuration is just that. It takes two readings at the same time though and plugs into the calculation program I have. Works like a champ.

But you can use parallels or adjustable parallels and mics and such as fits the bill for a particular application.

If you are aligning the gearbox output to the conveyor head pulley, a laser is "overkill". As slow as the head pulley turns, it certainly doesn't need to be laser aligned. Just use an indicator and the rim and face method and you will be plenty close enough in a very short period of time.

Sorry to say this, but someone who tries to use a laser for every alignment job just shows that he doesn't really understand the nuances of "effective" alignment.

Just a word of caution: if axial movement is a problem, index the rotor if using a face reading. Or, you can avoid this using two indicators on the same shaft thereby mimicing Indicator Reverse. The difference between the indicators/2 is the angle (Ind A - B / 2 per distance between) - you get the idea! Else see the for sale items and get your free book.