Aligning Motor to Shaft Question

[keebler303]

I have been tasked with fitting a new 20hp AC motor to a test dyno. I have to get the motor shaft and the machines drive shaft within .010" concentricity and 1/2 degree angle. How do I indicate the two shafts to verify proper alignment? I haven't thought of an easy way to do it yet. Any tricks?

Thanks
Matt

[neilw20]

That sort of accuracy can be achieved (assuming you are butting shaft ends to each other) with rulers/straight edges at 0 and 90 degree positions. Get 0 degrees right, do the same at 90 degrees, keep going back to the zero test until both are OK.
Alternatively mount a flat ended flange on each shaft, and align until you have have a very even gap using a piece of paper to check the gap.

[keebler303]

The ruler won't work so well as one shaft is 1 5/8" while the other is only 1". I could use flanges with the proper bores and same od to get them lined up.

Thanks for the ideas
Matt

[Geof]

Clamp the indicator to the machine shaft.

Line up the motor shaft as good as possible by eye.

Indicate on the motor shaft near the end and then three or four inches further back.

Adjust the motor to get the two readings the same; that is the same reading at the same position on the motor shaft. It does not matter if the motor shaft is not true to the machine shaft, if the TIR is the same at the end and further back the two shafts are parallel;

Now you have the shafts parallel you can figure out what direction to move the motor to get them aligned; if you are lucky it will be a case of shimming it up the same amount at all the mounting bolts.

[neilw20]

You just need a 5/16" piece of HSS tool stock as a precision spacer against the small shaft. Think outside the square. (oops circle).

[keebler303]

I ordered some 5/16 precision stock, I'll give it a go next week.

Thanks for the knowledge
Matt