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Jim Tabor

After looking at the post of Mike Meiser OSU red and white Unisaw a few weeks ago, I decided it would be fun to refurbished one. I have acquired not one, but three of them. One is a single phase and the other two are three phase. So here is the question…. does anyone have any experience with a TEMCo XR5 phase converter and how well it functions on a 3 HP, 3 PH Unisaw ? (Or any other brand of converter for that matter.) Also, one of them came with a Biesemeyer T-square guard and I know nothing about them. Does anyone really use them and do they have any value? Thanks.

David Kumm · 03-06-2013, 1:42 PM

A rotary phase converter will work just fine and it appears you have the proper size although if you ever get a 5 hp machine you will wish for a little bigger one. Temco, North American, Phoenix, Anderson, etc are all pretty much the same. It is the motor quality that is the variable. Kay and Arco are the two more expensive units and generally don't have start caps so they are a little different. If you get the Temco I would check with them that adding a parallel unit is easy as more often than not three phase is a slippery slope and soon you have bigger machines and bigger needs. Dave

Rod Sheridan · 03-06-2013, 3:12 PM

Jim, is there a reason you're going with a rotary converter rather than just adding a VFD to the saw?

The VFD would be less money, and give you braking and soft start.

Regards, Rod.

Jim Tabor · 03-06-2013, 8:03 PM

Sorry, my mistake. What I wanted to ask about is the XS5 which is a $49 static phase converter. I know nothing about them and was wondering how something so cheap could really work. Thanks, Jim

John McClanahan · 03-06-2013, 8:17 PM

You will loose 1/3 of the motor's horsepower, and the motor will run hotter. There may be a limit on how many times per hour the motor can be started.

John

Rick Fisher · 03-06-2013, 10:36 PM

Static is kinda cheezy but it will work .. as John said, you lose 1/3 of the power. If you push the motor when its on a static up to FLA on a regular basis, you will drastically shorten the life ..

A VFD would be a great choice.. under $200 .. good to go ..

Rich Riddle · 03-07-2013, 8:37 AM

Avoid static phase converters.

I am building a rotary phase converter and prefer them over the variable frequency drives. Many prefer the VFD's. If you look at the engineering of VFD's and talk to the engineers at the companies that produce VFD's, they will tell you they work best on motors that were manufactured in the last five years. None of the three-phase motors I have are that recent.

If you have a spare three phase motor, you can simply order the "control panel" for the rotary phase converter. If you can hook up eight wire connections (two to 220V coming in, three to the motor and three to the plug), then you can save hundreds of dollars on the rotary phase converter. If you want more information, feel free to send a message.

Greg Mueller · 03-07-2013, 9:18 AM

A 3 phase motor will run on single phase but will not start.

You can build a phase converter very easily.

You need a 3 phase induction motor. It's best to have one of higher rating (HP) than the motor you are trying to run
A pulley for that motor
A pull start rope off a lawnmower (etc)

Hook your 220 single phase through a switch to your 3 phase generator/motor (induction motor)
Hook your 3 phase saw motor to all three of the leads on the generator/motor.
Put the pulley on the generator/motor
Wrap the lawnmower starter rope around the pulley
Pull the starter rope to get the generator/motor spinning.
Flip on the power to the generator/motor.
It will pick itself up to speed.

The 3rd lead on the generator/motor will magically generate the 3rd phase of the 3 phase

I run an entire CNC machine shop off of this type "generator" (Actually 4 of them)
The capacitors in the store bought units are just to give the generator/motor a kick to get running. The rest is the same
You will get one leg of the 3 phase which will be slightly higher in voltage than the other two.

You can add another motor to get the generator/motor running and all sorts of inventive additions, but this is the basic unit.
It's pretty cheap to try. 3 phase used motors are usually inexpensive, as no one has power to run them.

Good luck
G

Jim Tabor · 03-07-2013, 9:44 AM

Thanks guys for the information.
Rich if I understand what you’re saying, a rotary phase converter is more or less a three phase motor with a phase converter, producing three phases for the next motor in line? I have a new single phase, 3 hp motor I bought from Chip Lindley that I plan to install in one of the saws so that will give me a spare three phase. As for hooking up some wires, should be no problem. Can the motors be the same size and with a rotary phase set-up do you still lose 1/3 of your power? Jim

David Kumm · 03-07-2013, 9:54 AM

You would be better off with a 5 hp motor for the RPC and you will have full power with it. While in theory newer motors run better- cooler with a vfd, the problems associated with older motors are usually at 440 volts. At 220-240 there won't be a problem with an old motor. The insulation on those was pretty tough stuff. Back when VOCs weren't a consideration. Dave

Greg Mueller · 03-07-2013, 9:56 AM

No "phase converter" necessary.
The 3 phase motor through induction generates the 3 phase

Rich Riddle · 03-07-2013, 10:14 AM

Jim,

Avoid doing what Greg advocates like the plague. That is what a "static" phase converter is. It's not good on the three-phase motor and reduces the output to 2/3 the horsepower of the three-phase motor. Far better options exist for you. I'm not keen on putting lawn-mower pulls on electric motors either. Sure it will work, but it's certainly not a best practice.

Brian Brightwell · 03-07-2013, 10:27 AM

I build a rotary converter on the cheap and am very satisfied. What my work didn't provide surplus store did.
This and a 10 Hp motor is all there is.

http://i773.photobucket.com/albums/y...l/P1010015.jpg
http://i773.photobucket.com/albums/y...l/P1010013.jpg

Greg Mueller · 03-07-2013, 10:46 AM

Originally Posted by Rich Riddle

Jim,

Avoid doing what Greg advocates like the plague. That is what a "static" phase converter is. It's not good on the three-phase motor and reduces the output to 2/3 the horsepower of the three-phase motor. Far better options exist for you. I'm not keen on putting lawn-mower pulls on electric motors either. Sure it will work, but it's certainly not a best practice.

Amazing....

That is NOT what a static phase converter is
It is referred to as a rotary phase converter

I have been running my shop off the method I have described for 30 years
It does not reduce the power of my CNC mills, my lathe or my knee mill, I can assure you.

But do what you like

Rich Riddle · 03-07-2013, 1:28 PM

Originally Posted by Greg Mueller

Amazing....

That is NOT what a static phase converter is
It is referred to as a rotary phase converter

I have been running my shop off the method I have described for 30 years
It does not reduce the power of my CNC mills, my lathe or my knee mill, I can assure you.

But do what you like

My first career background is electronics. I assure you what you are doing is a static phase converter. Here is the simplified defintion word-for-word from Wikipedia:

Alternatives exist to rotary phase converters for operation of three-phase equipment on a single-phase power supply.

Static phase converters are actually not a converter at all. They start the motor spinning and then "single-phase" the motor. They also require de-rating of the motor being run, typically to 60% or less of its three-phase rating. A 10 hp (7.5 kW) motor can be run only at 6 hp (4.5 kW). The power balance and thus motor efficiency is extremely poor. Failure to run a motor at reduced load will result in overheating and quite often destruction of the motor. Many machine manufacturers and dealers specifically state that the use of a static converter will render any warranty null and void.

Here is the link: http://en.wikipedia.org/wiki/Rotary_phase_converter

What works doesn't mean what is best. The higher output you get on one leg isn't a good thing. That's why rotary phase converters utilize run circuits to maintain voltages within 2% of each other. That's why 3-phase machine manufacturers void the warranty of machines powered by static converters. Your static converters are no different than anyone elses; they are operating at a reduced power rating. If your idler motor is 5 HP and your units are 3 HP you will never notice the difference. If you don't require tasks that require full power, you won't notice the difference.

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TEMCo Phase Converter Question

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