Saturday, October 13, 2018

3 Phase - Is It Worth Converting

This is a subject that often comes up in discussions and is seldom agreed on, as to efficiencies or DIY methods. The article I post here today, (from Fine Woodworking # 24) is not much different. It starts off with one mans simple set up, that seems to work well for him. However the size of his idler and the single phase starter, don't match up with claims of greater efficiency. However if your machines are 3 phase and you can't afford to convert to single phase or, as is often the case with larger machine shop equipment, the motor is built into the equipment and would require major modification to incorporate a new single phase motor, then this may be the way to go.

That may be the way to go, but I tend to agree with Mike Graetz's comment, in the following issue's comment section. If you must go with 3 phase, the method outlined in the "Editor's Note" below is a better way to go. It eliminates the single phase starter motor in favour of starter capacitors and reduces the size of the idler to more closely match the rest of your 3 phase motors. This increases the efficiency of the conversion, but you still won't be using less power than running a single phase motor. How ever there are still many benefits to three phase. Used three phase machines are often cheaper to purchase, and three phase motors are of simpler construction and easier to reverse, just switch any two leads.

I have lots of articles and plans on 3 phase conversion, but I have ruled it out long time ago. Most woodworking machines are easy to convert to single phase. My General band saw and Delta/Rockwell lathe were three phase so adding single phase motors was just part of the rebuild. I have passed on some three phase machine shop machines, but I think the weight of all that iron had something to do with it too.

"Boom" Workshop Grenade

In the same issue was an article reviewing jointer-planers by James A. Rome. In the article he relates the following mishap that he had in his shop. Fortunately he didn't get hurt, just scared, and I doubt he was easily distracted when working in the shop after this incident. The cutter head guard deflected the pieces of shrapnel, but the comparison to a grenade going off, is not far. 

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