Shaft Alignment 2

[jboy3333]

Since using laser alignment equipment for many years,I have become a little rusty in using dial indicators for alignment of pumps etc.All of a sudden i have been asked to witness shaft alignment using dial indicators (FACE and RIM) method. I still remember the REVERSE Indicator method and the fact that you need to half the TIR before plotting on the graph (can;t remember why)?

In the scenario i have at the moment, only the motor shaft can be rotated, and the Face and Rim method is being used. The final offset should have the Gerbox sitting 0.010" higher than the motor and with no angular offset. I have 4 questions.

(1)In this case, would i be correct in thinking that i should see a TIR of -0.010" at the bottom of the Gearbox hub (with bracket fixed to motor shaft and indictor zeroed at the top of the gearbox hub and rotated 180 degrees)proving the gearbox is indeed siting 0.010" higher?

(2)In theory, if i wanted to correct this offset and bring it into ZERO offset, should i install shims under the motor of 0.010" or should the TIR be halved and install 0.005" shims?

(3) Please explain why we half the TIR for reverse alignment before plotting on the graph?


(4)Can any one supply me with a Face and Rim alignment procedure?

 

[hydtools]

Does this help?

http://www.vibralign.com/ai/shaft_basics.html

Ted

 

[electricpete]

I have never aligned a machine enough, but I know only enough to be dangerous. So I'll take a guess and take my input with a grain of salt: (hopefully some others can chime in so you won't rely on my answer alone)

1)In this case , would i be correct in thinking that i should see a TIR of -0.010" at the bottom of the Gearbox hub (with bracket fixed to motor shaft and indictor zeroed at the top of the gearbox hub and rotated 180 degrees)proving the gearbox is indeed siting 0.010" higher?

Assuming: the Face and Rim method is being used, motor rotated and gearbox stationary, the gearbox is at it's final desired position of gearbox 10 mils higher, the dial indicator was zero'd at the 12:00 position, and bracket sag is negligible: Then when you rotate to 3:00/9:00 you should read -10 mils and at 6:00 you should read –20 mils.

(2)In theory, if i wanted to correct this offset and bring it into ZERO offset, should i install shims under the motor of 0.010" or should the TIR be halved and install 0.005" shims?

TIR is twice the offset. You should have 20 mil TIR and you should install 10 mils shim to bring a 10 mil offset down to 0.

(3) Please explain why we half the TIR for reverse alignment before plotting on the graph?

The dial indicator reverses it's orientation during the sweep. If you record dial indicator reading during the sweep you get a sinusoid and the TIR is the peak to peak value. But the offset is the peak difference in machine position (one half of the TIR).

Again... double-check my answers....


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[hydtools]

You plot half the TIR because TIR is Total Indicator Reading which is double the centerline offset. You shim to bring the centerlines into alignment; half the TIR.

Ted

 

[Kailee]

Here is a procedure for you.

A note of caution as well, if you are only turning the motor shaft, check for run out on the hub on the gear box hub 1st, otherwise it will throw off your adjustment readings.

Also, why is the motor offset so large? That seems to be quite a lot of thermal growth for a motor.

 

[jboy3333]

Thanks Guys.
All of your answers have blown the cob webs away from my dial indicator days. Thanks.