phase converter for 3 phase 5-HP Delta table saw

I don’t use phase converters but I have friends that do. The most recommended is a rotary phase converter. It runs off of single phase and generates the third leg of electricity to create three phase.

They work well but get an electrician for the hook-up.

An electrician will also be able to give you some good advice on getting one.

-- Todd A. Clippinger, Montana, http://amcraftsman.com

I have a rotary phase converter that can handle up to 15 HP, meaning I can run up to 3 tools at a time. I think you also need a transformer too, as the voltage on 3 phase is generally 550/560.

I spent around 6K for both units plus labour. I had a master electrician hook mine up.

It would be less $$$$ to change over the motor and switch!

-- http://www.furnituremann.ca/

I own 2 phase converters, but only use one. it’s a 5 – 7.5 HP version. It’s an electronic version that kicks in the Third phase to start the motor (tablesaw.) and then drops off.

The saw then continues to run on 2 phase current, (220 Volts, really single phase on 2 wires). I’ve run this setup for about 25 years. So essentially you only get 2/3 of the rated HP of the motor.

It was first hooked up to planer that has a 5hp motor. I bought a new looking motor for $5.00 and figured that would be a lot cheaper that a new 5 hp motor.

I bought mine on eBay for $70.00 – $120.00. I don’t remember the price.

I’m happy with the way it works. I burnt an earlier one out when the cord was laying in some wet sawdust and when I turned the saw on the power shorted out.

I hooked everything up myself. To reverse the motor you change any two of the three wires. So if your saw runs backward, you just reverse two of the leads.

On my magnetic switch on the saw the two hot wires are going through the coil contacts and the M line (manufactured power) goes through the switch.

I’ve been looking at making a rotary converter but haven’t been able to pick up 10 HP 3 phase motor to make one. I had my eyes on one but the junk yard scrapped it before I grabbed it.

Chuck Bender a LJ’er uses a rotary version in his shop.

-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †

My saw is 220 volts so I don’t use a transformer like Romas states.

-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †

I use a Phase-A-Matic on my 2HP vertical mill. I have used it for going on 12 years now with no problem.

Here’s the model for a 5HP one for $325:

http://www.drillspot.com/products/42118/Phase-A-Matic_PAM-900HD_Static_Phase_Converter

-- Gary, East TX -- The longest journey begins with a single step.

I did not get to finish my thought earlier because I got called off to breakfast.

Anyway, an electrician would be able to give you advice specific to your needs. The other guys are right in that you will only need a certain size for running just your tablesaw. But there are other things to consider such as hooking it up. As a remodeling contractor I suggest an electrician.

But another option may be to just replace the motor with a single phase. It will probably be less expensive.

-- Todd A. Clippinger, Montana, http://amcraftsman.com

I use a Kay Industries rotary phase converter. You should make sure you balance the voltages on the three legs so they are very close to each other. Voltages vary across the country and can affect the motor’s performance. I used a buck/boost transformer in conjunction with the phase converter to get my voltages within 1 volt of each other. Some electronic controlled switches are quite sensitive to voltage fluctuations between the three legs.
Kay Industries rates their converters differently than most other manufacturers in that they rate their converters for the maximum size motor theat can be started at a time. For example a 7.5 HP converter is rated to start one motor at a time up to 7.5 HP. Once started the converter can then start another one. One can run up to about 18 to 21 HP at a time by starting the motors up one at a time. Other companies rate their converters at the maximum Hp allowed on the converter. Also, the general rule of thumb is that the heavier the converter the better the performance. Stay away from light weight converters. Mine weighs about 260 lbs.
Here is a link to Kay : http://kayind.com/tech_center/sizing_tables.html

-- Oldworld, Fair Oaks, Ca

thanks for the inputs. I will probably buy a 3-hp, single phase motor. But I hate to throw away my 5hp motor which came with the saw.

Using 3-phase in a residential setting always makes me nervous. All it takes is that one leg dropping out for any reason and single phase the motor which can fry it in a heartbeat. Most recently I had a 3-phase refrigeration compressor lose the one leg all because the 3rd pole of the breaker failed….very expensive repair.

I have installed a few of them in the last 40 yrs. Changing the motor to single phase is what I wouild recommend unless you need 3 phase for equipment that can’t be retrofited.

-- Debt is nothing more than the 21st Century's form of slavery.

Karson, what you have isn’t an electronic phase converter. It’s actually called a static conveter.

Lazy a VFD from www.factorymation.com would be my first option. A heavy duty staic from www.phase-a-matic or others would be another option. With a static you will lose 2/3’s power which will put you in the 3 hp range anyway. Call up each vendor and talk to their tech to fully explain it better. You are getting confusing info on the forums form folks who don’t undersatnd the virtues and problems of each way to do this.

Best place to buy the static is Enco…best prices

-- Whatever!

Rick You are absolutly correct. It’s a phase converter and it even looks like the one in the Enco catalog.

-- What happens in the workshop stays in the workshop. No wait that doesn't sound right. Karson Southern Delaware karson_morrison@bigfoot.com †

As Rick has suggested I would go with a VFD. The one you need is here
I have a 2hp VFD powering my ‘68 unisaw and I must say I love it. The installation was very easy and straight forward. Its as close to plug and play as you can get. I would most definately stay away from a static converter. They are hard on motors. If you decide to go with a rotary converter send me a PM and I can send you more info.

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

One of the issues with modern VFDs is the requirement for VFD rated motors. Depending the cycles they are running at, they can blow out the insulation on older motors. You always run the risk of putting a lot of noise on the line that interferes with all kinds of electronic equipment. All of out modern electronic equipment; computers, electronic balllasts and VFDs raise problems with efficiency known as power factor. That is having the current our of sync with the voltage.

Everyone always says to get an electrician to wire it. I have been for 40 yrs+. My first choice would be to change the motor to 240 v single phase if it is an option as in this case and other 3 phase considerations are not a requirement. Especially in a residential enviornment.

-- Debt is nothing more than the 21st Century's form of slavery.

what is the difference between VFD and a static converter? I see that I can buy a rotary converter about $500. I must say that woodworking is my weekend hobby. I do not really require a 5-hp saw. I got it from the IRS auction, and realized that it was a 3-phase saw.

The static phase converter makes 3 phase power to run the motor at a set voltage. VFD, variable frequency drive will run the motor at a varying speed, voltage and frequency. One of the advantages of a VFD would be soft starting the motor with out the dramatic inrush current you see dimming the lights a bit. I wouldn’t do it for that alone on a table saw starting without a load.

-- Debt is nothing more than the 21st Century's form of slavery.

Well I feel that in this instance I have to agree 100% with Topamax’s comment, when do you foresee to need 5HP in your home workshop? what size lumber do you expect to process there?
If 3HP will fit the bill there will be no detrimental effects on your saw, it will still outperform any smaller sized saw.
And as stated by others, Static Voltage converters only cheat the lack of the third phase, VFD’s on the other hand have issues generating noise that could upset the neighbors when they watch TV or interfere with other electronics devices in your house. Rotary converters would be the way to go but are very expensive you would certainly save money by retrofitting a 3HP motor.
There those are my thoughts on this but in the end it is your choice, at least you have a fair amount of info to help you decide which route you will take, hey and when you do let us know and also how it persforms.

I would agree with Jerry and Topamax, if it’s possible, change the motor to a single phase 240v. I’ve been an electrician for a few years and am currently going back to school for more training in industrial electical and we had an old Powermatic 3 phase drill press we wanted to sell but concluded it would be easier, economical, if we changed the motor out to a single phase. Plus if you do that, an industry in your area may buy the 3 phase motor from you.

thanks everyone for the insightful suggestions. I am convinced that a new 3HP, single phase motor is the way to go. I have to find someone who can buy my 5hp, 3phase motor. I hope the rewiring from 3phase to single phase will not be a problem. I tried to sell the saw on craigslist, but no interested buyers yet. I will certainly post my final decision – may not be soon though. well you can figure that out from name – lazyborn

The rewire shouldn’t be a problem, just use two of the three hots at the on the cord, at the switch and going to the motor.

-- Debt is nothing more than the 21st Century's form of slavery.

I use a 15 HP rotary in my machine shop but as stated above, I would just get a single phase motor to replace your three phase 5 HP. If you had multiple machines needing 3 phase then it may make more sence to go with the converter but since you only have the one, it would prob be better to replace it. A 3 HP motoe should do well for you. The 3 HP on my Unisaw has plenty enough power to sling lumber into the concrete wall behind it!

-- Scott, South Carolina

I think everyone has this one covered for you….but I just wanted to add that we have 3 phase in our shop…for welding machines…etc….and there is a 5 and a 3 Hp set of band saws in here….of course they are for cutting metal. The 3 Hp gets most of the work as it is easier to set up and use…but as for guts…that lil 3HP cuts some big cuts just fine…..I don’t think you really would find any use for the additional Hp on that saw…especially seeing the costs to acquire it…...

-- Woodworking.....My small slice of heaven!

As a pro contractor I would just cut out all the static and listen to Topamax. If he was in town I would use him on my jobs.

-- Todd A. Clippinger, Montana, http://amcraftsman.com

Thanks for the confidence in me Todd ;-)) I finally got used to people saying, “So you’re Bob…......” when I met them. It was a bit embarrassing at first, but I got used to it. My reputation spread from WA to Boise. Looks like I need to watch it in MT now!!! :-))

-- Debt is nothing more than the 21st Century's form of slavery.

I think you can use two transformers to get 3 phase. There’s a way to hook it up but I don’t have an Ugly’s here at the house. All of my engineering books are on my book self in my office. :( I’ll see if I find it…

Chunk

-- Chunk

You might get close with 2 3 phase motors, but transformers aren’t gonna cut it unless one of them has 3 phase coming in :-)) Ugly’s ain’t gonna help much on this one!

-- Debt is nothing more than the 21st Century's form of slavery.

What I was thinking of is called an Open Delta and you need 3 phase to start with. NM.

I still think there’s way to do it. I removed an old AB 1336 VFD once and a gave it to a guy that I used to work with so that he could run his TS with it. He also had a transformer that he connected backwards to use as a step up transformer but I don’t remember how he got 3 phase to start with. It sucks getting old.

Chunk

-- Chunk

I remember now! lol

He only used single phase into the VFD and the VFD’s output is 3 phase. DUH! You think I would have remember because I have the exact same thing on my drill press! 120 1 phase in, 240 3 phase out. I’m so stupid.

-- Chunk

He had to have 3 phases available. I’ve connected transformers to step up when the customer had 208 or 240 and needed to get to 480 for a particular piece of equipment. Gotta be careful, I found one that some one had grounded the low side. The power company had a bad habit of single phasing about once a week. They burned up a transformer every time it happened. That’s when I got involved to find out why:-))

-- Debt is nothing more than the 21st Century's form of slavery.

Looks like I sent you a bum steer!! :-)) Sinlel phase into a VFD will output 3 phase as long as it’s over sized about 40%. It’s pretty amazing what modern electronics has accompiished in the last 20 yrs.

-- Debt is nothing more than the 21st Century's form of slavery.

Hi all,

I haven’t been on here in a while. We ar expecting are first child in Feb…so needless to say things are rather busy. Plus I’m building the crib.

Anyway….I know there are those on here that don’t like the idea of this but, I built my on phase converter last year for a 5hp delta unisaw and it has been awesome. It is a rotary type. If you have the money to buy buy all means do it. It took me 2 months to figure out how to build it and 1 day to actually build it. There are plans on the internet and you can get all the parts minus the motor from Grainger for less than $75….let me know if you want to see mine. I’m not an electrician but your welcome to see what I built. Also, it has been used ALOT in the last 1-1/2 years.

Nothing wrong with building your own if it works. An aquaintance called me for a price to install a phase converter after he wouldn’t listen to advise about wiring his commercial shop. Price to do it right was too high, again. Next time I heard from him he wanted to know why he had to spin the homemade one every morning to start his comperssor. I told him to be sure and spin it the right way or his compressor would be going backwards :-)) About a year later, he wanted me to figure out why his compressor motor burned up. The inefficiencies of the homemade device were too much for the constant load in a 6 bay auto shop. An intermittent load like a table saw for a hobbist is an entirely different matter. All you need to make a basic 3 phase is another 3 pahse motor idling on the line between the single phase power sourde and teh 3 pahse equipment:-))

-- Debt is nothing more than the 21st Century's form of slavery.

Brian, did you know that for three phase motors 1 hp and under you can run the VFD on 120 volts. On that drill press it would have been cheaper to use a VFD than swap the motor and deal with the switch plus you would have the bells and whistles such as variable speed and doubling the motors rated rpm. In my book for $120 that’s a better deal than swapping the motor for a single phase motor.

There is little demand for used three phase motors. Usually at scrap metal prices.

There is so much confusion on phase conversion. Many electirians don’t even know. I’ve had some tell me it was impossible to do. Should have seen the look on their faces when I showed them the options.

Can anyone here list the four options for phase conversion… not counting motor swaps??!

-- Whatever!

What most electricians don’t know kept me working for 40 yrs when a lot of them were setting at home. Most of them are a bit jealous when I tell them I haven’t installed a light fixture in the last 20 years :-)) :-))

Sure, the cheapest is run a 3 phase motor on the line. Static converters work ok for no load stating like saw or grinder. Rotary converters are necessary for loaded starts such as pumps or compressors. VFD is always an option. I’ve never really thought about it, but I suppose you could use a soft start. Pick the one that fits your budget and doesn’t drive you neighbors nuts interfering with all their wireless gadgets, TV and radio reception ;-))

One thing all the VFD advocates seems to miss is the potential for easily burning up an old motor with a VFD taking a short cut to 3 phases. When my meggar used to show 15K ohms +, the motor was good for ever. The manufacturers all said 10 were good enuf, but in my experience, it wasn’t. When hooking up VFDs to old motors, their insulation isn’t made to operate in the kilo and mega hertz range, they are 60 hertz devices.
Modern drives are showing the motors a nearly perfect sine wave at the expense of insulation values. They do it by switching the DC off and on 100’s of thousands of times / second. Every piece of equipment I have work on in the last decade, maybe a little longer, we have swapped out the old motor for a drive rated motor when installing a VFD.

-- Debt is nothing more than the 21st Century's form of slavery.

Tim…I’ll be sending you an email as soon as I can get 5 posts on here…lol. I’d be interested in seeing how you built your phase converter.

Mitch H… In Canada

Tim… I’d be interested in seeing specifically how YOU did yours. I suspect you used an old motor and a capacitor to start it??? Can you post the diagram on here??

-- Debt is nothing more than the 21st Century's form of slavery.

Here is the VFD I have installed to run the unisaw that I recently restored. It is 220V single phase input and 220V 3ph output. It is installed in a metal enclosure, 12×12x8, that is mounted to the wall. I cut holes and put in an outlet for the 3ph feed to the saw. I still need to add the second outlet for the low voltage,12V, control to the switch on the saw. The total cost is about $225. I used the plug/putlet so if in the future I get other 3ph machines I can easily plug them in and not have to dedicate a VFD for each machine. I must say that after running the saw for a while I am very impressed with both the VFD and 3ph power. It is very quiet and smooth. If I were to do it all over again I dont think I would change a thing.

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com

If you want an example of how to build an RPC, rotary phase converter look here

-- My job is to give my kids things to discuss with their therapist....medic20447@gmail.com