Powering Unisaw Options?

[Charlie Velasquez]

My Unisaw options?

I hope I made a good decision, but won't know till I make my next one and I need help with that.

When a local Brammer factory shut down In the late-80's, a friend purchased a Unisaw 34-450 and 100 cherry, raised panel, cabinet doors with the intention of redoing his kitchen and basement. Poor health hit him and these sat undisturbed till now. He decided to sell these to me for a very good price because he felt I would "appreciate" them. So now, I have a lot of doors and a saw!

However, before it is a bona-fide gloat, I need to get the THREE-PHASE saw running. Options are:

A) Replace motor with a single phase

B) Buy/build a converter.

A) The current motor is a 3450rpm, Baldor 2hp running on 220v three phase. The advantage to switching motors is I could get a 3hp or 5hp motor. If I did this would I need to replace the switch or would it still be OK since it would still be 220v? Anything else?

B) I would like to add additional pieces of equipment, and it seems used three phase are cheaper than single phase (a single phase 6" jointer recently sold for $320, while an 8" jointer of about same vintage and condition, but three phase, sold for $300; and this reduction in price of three phase seems to be common). If I went this route then, there are several kinds of converters. I may have a line on a 5hp three phase motor so I don't think I would look at a static converter, but several posters in the threads I have read advocated a "VFD".
I also read somewhere there is a new kind of a "digital" converter (phase perfect)

What are some things I should be aware of to help me make this decision. Thanks for your help.

[Dev Emch]

Depends on what your doing and where your going. Yes, three phase 8 inch jointers are not as valuable as single phase ones. One reason is that many three phase guys running converters arnt looking for an 8 inch jointer.... they are looking for 12 and 16 inch jointers.

Three phase motors cost less than single phase motors and often the three phase electricals also cost less. Industry drives this market and there is little use for single phase electricals in hard core industry.

It would be nice to up your motor from 2 to 3 or 5 ponies. But putting a 5 hp single phase baldor into the saw with electricals may cost more than a new saw so watch out here!

Lastly there is nothing wrong with using a converter. They work and they are wonderful.

No reason to pursue the phase perfect. They use digital signal processors to manufacture three phase power and its a gimmick. Yes they are superior in their waveform; however, at what cost? There is nothing to fix or repair and the box is loaded with embedded software systems. A rotary converter is a box full of motor windings, rotors, bearings, capacitors and some relays and a few bobs of wire. Much easier to fab parts for or find exchange parts. Your really going to need quite an operation to justify going with a phase perfect versus another converter such as a kay.

[Steve Schoene]

A lot depends on your "tinker" factor. If it were me, I would replace the motor with a 3hp. single phase motor. It can be had for roughly $360. You would have no complications, and you would have meaningfully more power than the 2 hp with converter.

Dev likes the idea of having a box with rotors, capacitors and relays to fix or repair. I admire guys like that, but that's about farthest from my idea of fun as can be. I tend to fall in the K.I.S.S. camp.

[Chris Rosenberger]

If you are looking at adding several 3ph machines later, than go with the converter. If not, than change the motor to single phase. Converters can be a hassle. Someone on ebay is selling new Leeson 4hp 1ph motors for $320 delivered & 3hp 1ph for $290. As for the switch. You may be able to use the one you have. It depends on the type you have. At the very least you would have to change the overload for a higher amp of the single phase motor.

[Mike Hollingsworth]

I can only add that a phase converter worked great for me until I was able to get a single phase machine. Adding a $20 5hp 3ph motor to a static converter made it into a rotary converter. This powered up my 2hp PM66 which never bogged down.
If you have access to 3ph equipment this can be a very economical way to collect tools.

mjh