Motor alignment

[paulie01]

I have a job to replace a 50 HP motor for a water pump. Is there a way to align the motor, coupling and pump.

 

[don_resqcapt19]

You need special equipment to do it right.

 

[Prene13]

Call a Millwright

 

[gar]

100208-2211 EST

Use a laser alignment tool.

Lacking that use a dial indicator attached to one shaft and rotated about the other. This does not easily solve the problem of getting the two axes parallel, and therefore concentric.

Off of the mounting surfaces you can probably assume parallelism. It is in the other axis that it is harder. When you try to align within 0.001" is can take hours, and still may not be correct.

Then use a shaft coupling that is not too sensitive to alignment.

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[wptski]

Is the motor/base designed to use fitting shims? If so, you can really get fussy! If not, you can use a indicator like "gar" said. Depending on the type coupling, remove the spider or whatever, move the drivers as close as possible and guage the space to get it square. If you can the coupling pushed back enough, you can use a straight edge if the shafts are the same diameter, if not, make up the half the diameter difference with some stock and then use a straight edge.

 

[C3PO]

I also reccommend using a laser alignment tool. Otherwise you take the chance of wearing out the pump and motor bearings prematurely

 

[wptski]

I also reccommend using a laser alignment tool. Otherwise you take the chance of wearing out the pump and motor bearings prematurely

They are difficult to use in close quarters unless you have a special fixture. We had a guy assigned to laser aligning full time and I've never seen him do a motor, not that he never did just never did enough to notice.

 

[eric9822]

I have a job to replace a 50 HP motor for a water pump. Is there a way to align the motor, coupling and pump.

If you don't have the equipment and the knowledge then you should sub contract that piece out. If the alignment is off you could very well destroy the bearings in the motor and the pump.

 

[gar]

100208-2333 EST

At Dana Columbia on a production test machine for noise and other tests of the Ford Aerostar transfer case we used a service that did laser alignment of a 50 HP DC motor coupled to a shaft in a sleeve bearing. This was quite successful. Also had to dynamically balance the motors because this was a vibration sensitive test, there were three motors, one for each shaft. The total test time was probably about 40 seconds. The motors had to be rapidly ramped up and down, 0 to 2500 RPM, in synchronization with different torque loading.

In a different application, non rotating, a pinion position machine at Ford Sterling laser alignment was tried, but the dial indicator method worked better.

In any event it takes the skill of an experienced person, most likely a machine repairman or toolmaker. Millwrights are usually more for the rough stuff. It will depend upon the plant what skill levels exist.

Note, Bill is a highly experienced machine repairman so his comments are more important than mine.

.

 

[John Paul]

Call a Millwright

I agree. Get mechanical on the job. Those poor guys always had the back-breaking end of the job.

 

[mcclary's electrical]

We align all motors we install up to 400 hp,,,,above that, we use a company called Electrical Equipment. They use a laser alignment tool. They did a 7000 rpm turbine for a 1 megawatt 4160 generator. We also had them do a 2500 hp 4160v motor. But run very smoothly and are worth the money.

 

[wptski]

100208-2333 EST

In a different application, non rotating, a pinion position machine at Ford Sterling laser alignment was tried, but the dial indicator method worked better.

gar:

Yes, I've seen a few laser jobs that didn't turn out well. I think that it can get pretty confusing at times and a old school indicator can and often works better.

You probably knew the laser person at Ford Sterling? One problem there was that he worked alone with nobody to challenge his thoughts. He retired and I'm sure nobody replaced him.