Three phase converted to single phase

[Scott Brandstetter]

I am in no way an electrician and could use some help. I have stumbled upon some very good woodworking equipment but the seller tells me it is Three phase. I have read a bit about converters that will take it to single phase but I simply don't know if this is realistic and what all is involved. Anyone with knowledge that wouldn't mind responding, I would appreciate it. Not sure if it matters but the items I am looking at is a table saw and an 8 inch jointer. Thanks in advance for the help.

[John Patricks]

You can do it a few ways, but the easiest and most efficient way is with a phase converter. Your machines would also hold their value this way as opposed to hacking with the circuitry or compromising with a single phase motor.

There are 2 types of converters static and rotary. Static being the cheaper choice, but not necessarily the best.

A static converter is fed 220 single phase and uses it to shoot a temporary power shot to the 3rd three phase leg on your motor at start up. This, along with the 2 single phase legs you have in the building get the motor going. Then that third leg that was surged during startup goes dead and the motor runs on single phase 220. As such the motor runs at 2/3 of the power rating.
A rotary converter uses the single phase 220v input to spin a 3-phase motor that is incorporated into its construction. Just like with the static converter it runs on single phase 220v. However since it is a 3-phase motor the third leg is actually generating power, somewhat like when a generator is running. This third leg is sent to your machine motor along with the 220v that is in your building. Now you have 3 power legs going to your 3-phase machine motor so you have full power.

Concerning your question if it's realistic, well that depends on the machinery. What brand and condition is the saw and jointer?

John

[Matt Day]

I have a Variable Frequency Drive (VFD) on my bandsaw and it works great. It's a TECO FM50 and cost about $200 and was relatively easy to wire. I think it can be wired for multiple machines as long as only one machine is used at a time, but I am not certain. The folks at factorymation would be able to answer that for sure.

John covered the other two options nicely.

[Moses Yoder]

I bought a PM 66 with a 1-1/2 horse 3 phase motor and wired an inverter to it myself and it works great. I bought the inverter new off ebay if I remember right. They have to be sized to fit your motor, the bigger the motor the more expensive the inverter. This saw runs off a single phase 220 volt 20 amp circuit now. A nice thing about the inverter is overload protection; if the motor draws too many amps it simply shuts off the inverter. I would go this route over a phase converter simply because it is less expensive if you are only doing a couple machines and it takes up no space. Here is a pic of my saw loaded down with crap, it is clean right now, but you can clearly see the inverter on the left end of the saw; it is the blue box and contains the on/off buttons.

2 saws.jpg

[Rick Fisher]

3hp and under, use a Variable Frequency Drive, or VFD .. the Teco FM-50 mentioned above is as good a choice as any.
You will need one for each tool.

Once you mount a VFD on an 8" Jointer, its pretty much a single phase machine. The resale value goes way up because anyone can run it ..

[David Kumm]

Check out the start controls on each machine. If manual, you don't need to change much machine wiring to use a vfd so they can be used at a reasonable cost. If magnetic you will need to bypass them. Once you go three phase you will likely continue to acquire machines as three phase is really a better option as HP increases. Long term the rotary converter or Phase Perfect is the answer. Avoid static. Not what you want for a bunch of older machines. Dave

[Bill Adamsen]

Did not realize that magnetic controls don't work with a VFD - thanks Dave.

I have both a VFD in the shop (powers a dust collector) and rotary phase converter (RPC - powers shaper, jointer, planer, tablesaw, bandsaw, mortisers). I also have a transformer "post 3-phase conversion" for some 440/480 dedicated machinery. The VFD has the attractiveness of all the programming features - such as slow start and stop, JOG, emergency stop, reverse, frequency [speed] control - which tend to be quite attractive for machines like lathes, but can be useful for almost anything. For instance, I use the slow start and stop on my dust collector which avoids that huge current spike as the machine starts. Not an expert here, but my understanding is that VFDs tend to be dedicated to "a" machine, especially if programmed. So it would be a 1:1 relationship - a new VFD for each machine - which could get expensive. Whereas the RPC can be used - for example - to power up a load center and distribute power to a bunch of machines, as in my shop. Having that flexibility opens up lots of opportunities when considering new equipment.


The machine I have on the dedicated 440/480 (Yates Mortiser) would benefit from variable speed. This is strictly theoretical, but had I thought it out better, I would have transformed the single phase from 240 to 480, and then used a 480 volt VFD to power up the machine. Benefits would have been that single phase transformers are much cheaper than 3-phase transformers, and the VFD would have programming options such as frequency (speed) control. Oh well!

[Scott Brandstetter]

Thanks to everyone for the information. I have to get more information from the seller but here is what I have so far. He is asking $4,000 for an Oliver 5hp Table saw, PM 8 inch and 6 inch jointers, PM Lathe, not sure of size, and three pickup trucks full of white oak and cherry kiln dried (2 of the 3 is cherry). I didn't go into more details with the seller because when I heard 3 phase I thought I'd better look into that first. My only real need right now is for the 8 inch jointer but if it's a deal, would buy the group and sell.

[Keith Hankins]

I use 3 phase equipment and they are great! If you only have one tool to buy then a VFD is a cheap option. If however you are going to have more than one, then I woould put in an American Rotary phase converter. No matter which one you put in make sure the 3 leggs are balance. You can finde plans out there just to make one, however the balacned part is much more difficult. When I went digging for my solution, American Rotary was the one from the vintage macinery forum that was the higgest cudo's. I went with the 10hp unit, and have not looked back. 3 phase tools are are cheaper to acquire too. Finally they are made in America. Good luck.

[David Kumm]

A used Kay or Arco are RPC options too. They build with a very heavy frame motor and are top of the food chain. If you find a used Phase Perfect you should also consider it. I've bought four over the years, all at 1/2 price or less and all performed flawlessly. A step above a regular rotary. Dave

[Moses Yoder]

If you are buying three phase tools to resell keep in mind they will be hard to sell. You would probably end up storing them for some time while you found a buyer. I bought my three phase PM 66 for $80 and a used bow.

[Scott Brandstetter]

It's funny you mention this Moses. I was really caught off guard with the seller when I spoke to him. I didn't understand the 3 phase impact then he acted like he has had the tools for a while. Maybe that is why. I really only want the 8 inch jointer and he wants to sell them as a group. If he were to sell individually, I guess your suggesting I could get a real deal. And if I can do the conversion to single phase for around $200, not bad. Need to talk to my electrician.

If you are buying three phase tools to resell keep in mind they will be hard to sell. You would probably end up storing them for some time while you found a buyer. I bought my three phase PM 66 for $80 and a used bow.

[John Sanford]

Whereas the RPC can be used - for example - to power up a load center and distribute power to a bunch of machines, as in my shop. Having that flexibility opens up lots of opportunities when considering new equipment.

Could you provide more details on this load center. Pics, etc.

[Anthony Whitesell]

Magnetic controls do work with VFDs. But of course there is a but. There are magnetic starters for 3 phase machines, either native three phase, phase converter or VFD. The designs for magnetic starters for single phase, 3 phase, phase converter 3 phase, and VFD 3 phase are all different. Some of the parts are interchangeable between some of them, some are not. I have an old Rockwell drill press with a 240V 3 phase motor powered by 220V single phase via a single phase to 3 phase VFD. The controls design not only includes the VFD, but also thermal and current overload protection and a magnetic starter. In the event of a recovering from a power loss or other fault the drill press motor will not start until I press the start button again.

[Rick Fisher]

Could you provide more details on this load center. Pics, etc.

I have a Phase Perfect 20hp Converter and a 3 phase Siemens panel.



The Converter serves the same function as an RPC.. In this case its fed by a 100amp breaker and #1 Aluminum Tec Cable. I operate the entire system with the 100 amp Breaker. From the Converter to the load center is only 60amps.. If my memory serves, that is #4 Copper..



This was about 4 years ago.. Today I run a small wide belt ( 12hp) .. Edge Sander ( 4hp).. and a Jointer (4hp).. I am restoring a Griggio 20" Planer (9hp ) and hope to have it running by Xmas.



The 3 phase machinery is connected to the panel by Tec Cable.. The first 2 tools where hard wired, I used a 4 prong plug and receptacle for the edge sander..



Basically you walk into the shop.. hit the 100 amp breaker.. Wait 8 seconds, hear a clunk.. and all the 3 phase machinery is hot. Lots of fella's have a system like this.. Its pricey up front, but really convenient in the long run.

That Siemens panel will only hold 6 breakers. When the planer is running, I will have 4 spots filled. To add in a 9hp Planer, I snap in a 3 phase breaker, run (Guessing) #10 Tec Cable to the planer, and either install a plug ($$$) .. or hard-wire it in .. Its pretty simple after its all set up ..