I have a beaudry no 100 power hammer it has a 3 phase motor on it does anybody know what size hp it is ? 

Does it have a straight 6 or V8?

That is not enough information from you to render a useful answer. What does the badge on the motor say? Have you checked The Powerhammer book? Asked the people who make Beaudry power hammers?

Welcome aboard, glad to have you. if you put your general location in the header you'll have a much better chance of meeting up with members living within visiting distance.

Frosty The Lucky.

If I had the tag to the motor I wouldn’t be asking with such little info this is all it has on it.  And the company isn’t around anymore. 

Sorry for the snark, it sneaks up on me sometimes. Have you checked with, "Beaudry & Co. site? I only made a quick skim and it appears they have information for every power hammer since the company was founded to today. It's a commercial site so I'll PM the link to you.

Frosty The Lucky.

Welcome from the Ozark mountains.

Usually there is a plate on the motor itself, may be underneath or obscured by the mounting plates.

I can't control the wind, all I can do is adjust my sail’s.
Semper Paratus

 

For a 100 pound hammer a three hp is typical. Some older machines might have a smaller motor, and it really doesn’t hurt to go up to 5hp.

I usually put 5 hp 3ph 900 rpm motors on motor driven clutch model 100# Beaudry champions. Are  you going to use 3ph power ? 

Here is a factory Sheet for your hammer 5 hp 850 rpm usually 3ph was recommended the hammers never came with a motor unless customer shipped them a motor. paper is from 1943 hope it helps 

If your motor is up and running (photo shows it already powered), you can put to work and measure the amp draw at each of the hot legs using a strap around (clamp on) ammeter.  This will give you a direct measure of the brake horsepower currently required by the motor in question.