Experience with a phase converter with 3 phase table saw.

[fRED mCnEILL]

From time to time someone on this forum brings up 3 phase motors. Tools with 3 phase motors seem to be cheaper than single phase because I'm sure 3 phase is foreign to many of us. So I thought I would describe my experience to show how easy it is.

I purchased a used Rockwell table saw for my son that has a 3 phase 3hp motor.

I have experience with 3 phase motors as my own General table saw has a 3 phase motor. As a phase converter I bought a rotary phase converter. This setup requires that I initially have to start the motor on the phase converter before starting the tablesaw. Its an extra step that I don't have a problem doing but I wanted a simpler solution for my son as he is not as mechanically inclined as I am.

At any rate I bought a static phase converter on Ebay for $100 and wired in it. Once it is connected to the electrical panel it is simply a matter of plugging the saw in and using it. Just like you would with a single phase power source. A static converter reduces the power output of the motor by 1/3 so the 3 hp motor puts out 2 hp which is plenty of power.

It literally is that easy.

[Matt Day]

A bit more complicated is a VFD, because you need to have a switch wired directly to the VFD - as simple as a light switch and speaker wire if that'll do. But, the vfd gives you full power and can do other cool things like adjusting the acceleration and deceleration times and reversing the motor.

3Hp VFD's can be had for as little as $116 on eBay.

[David Kumm]

There are some caveats. A table seeing light use works fine as long as you don't run it at 2/3 full for extended periods as the single phasing tends to generate heat. The 2/3 rule is also an approximation so you need to be careful to stay under that. Larger motors may be delta wound ( as are many Euro motors ) and they will only develop half their ratings so you need to really watch them. Given that a vfd costs less than $100 more ( and some wiring expertise ) it is a better solution. Also better with a standard size motor rather than a proprietary design that is costly to rewind. I'd not use a static on a planer, sander, bandsaw for resawing or dust collector. Dave

[Bill Dufour]

A VFD allows use of a lower ampacity circuit since there is much lower staring surge current. The switches are also lower voltage so easier to add some extra switches on the back or sides.
Bill

[Chris Hachet]

A VFD provides excellent protection for the motor and soft start and an orderly shut down of equipment. I really like machines not starting with a jolt and the blade stopping sooner rather than later.

A VFD also means that wiring the shop is simpler, since I can move equipment around and single phase and three phase equipment can easily share the same outlet-circuit if I want to re organize the shop.

Another plus is that every time I am servicing a piece of equipment I am not making saw dust, and a phase converter is just one more piece of equipment to service. Were I to install a phase converter, it would be from a reputable company like American Rotary. I would want a UL listing for liability and insurance reasons. My son works for an insurance company and likes to tell horror stories...I trust myself to build a rotary converter, I do not trust an insurance company not to throw me under the bus if something ever happened.

Aesthetically, I also like small motor control centers near equipment...it makes my home workshop look more like an actual work shop and not just a small hobby shop where I putter with wood.

[Chris Hachet]

But Kudos to the Op for keeping the three phase motor...I love three phase motors...