Motor Change-Out for a Shaper

Does it make more sense to change from a 3-phase to a 1-phase motor, or to invest in a rotary phase converter? Alternatives are pondered in this thread from the Solid Wood Machining forum. November 13, 2005

I have purchased a T110 Shaper, and want to know if it is possible to change the 6.6 HP 3 phase motor to a 5 HP single phase motor. Would a Rotophase converter do better?

Forum Responses
(Solid Wood Machining Forum)
From contributor P:
Yes, from what I recall, you can put in a 4.8 hp motor. You will have to change the starter switch and some other components. Call SCM group for details. I did the same thing to my T50 shaper. At the time I did not have a phase converter. My advice would be to stay with the 6.6 hp and go three phase. The 4.8 hp has plenty of power, but I could use the 6.6 hp.

From contributor G:
You could also look for a variable frequency drive to make 3 ph. That will also give you speed control too. It may be about the same cost and easier than buying a new motor and starter etc.

From contributor R:
An inverter for that size motor would be very expensive and pointless as the machine already has multiple speeds via a step pulley. A rotary phase converter would be about the same as an after market motor but would have the advantage of:

A) You wouldn't have to change out the motor and electrics on the machine.

B) You could run other 3 phase equipment you might acquire with the same unit.

The least expensive option is to us a static phase converter, these are relatively inexpensive but you will lose 1/3 the rated HP as it is using the shaper motor to generate the third phase. However 4.4HP would probably be fine for most work.

From contributor M:
As I see, multiple people have responded to your question with the suggestion that you look into a rotary phase converter or inverter. These are good options for a couple of reasons. Both of these units can be installed with out making any changes to your machine which would affect your warranty if it is new. By installing a different motor on your machine you also are making a modification. According to ANSI O1.1 2004 Safety Standard the modifier of a machine assumes the liability in case of an accident. Many customers commonly use a quality phase converter as a solution.

From contributor M:
Another note of importance is that if you use a variable speed inverter you need to be cautious about this option for a good reason. With variable speed inverters, if you slow the motor down too slow, the mechanical fan on the motor may not be able to keep it cool. This could cause you to damage the motor of the machine. You should research this in depth if you intend to make this change. If you need to go this route, you may need to add an electric fan to the motor to cool it. Once again, at that point this would modify the machine.