3 phase woodworking power tools

[Piston]

As some of you know, I'm going to be starting a little "transformation" of my garage to a woodworking shop.  Also, as some of you know, I don't know a whole lot about woodworking yet.  :D   And even LESS about electricity.

I was perusing craigslist and am finding an awful lot of older 3 phase power equipment for sale, for instance, I found a Wadkin 12" restored table saw that has a 5hp 3 phase motor that would look nice in my garage.  Although I have no idea what Wadkin even is, or if it's good/bad/indifferent, it made me question, can I get 3 phase into my garage, from my standard 200amp service, or is it something totally different? 
I believe it's something totally different, and I can't do it unless I pay the man some more money, but just wanted to see if 3 phase equipment can be used in a garage/shop without too much hassle.

I'm fully prepared for a "No you idiot" answer, just want to confirm my suspicions  :D

[Ianab]

Probably not impossible.

You can create 3-phase power from single phase using a magic box called a Phase Converter. It's another 3 phase motor and some capacitors that magically transforms the power to the 3 phase that the motors need. It's something that can be built with scrounged parts as old 3 phase motors can often be bought for "scrap" prices.

Al Smith knows a lot about this stuff, hopefully he will be along to explain better. I also believe Bibbyman runs his 3-Phase Woodmizer via one.

Ian

[TimRB]

I don't know what you have in mind in the way of things you'd like to build, but a 12 inch table saw is a honking big machine. Not even many professionals need a saw that big.  You might consider something smaller--say a 10 inch.  That will simplify your power requirements, not to mention the cost of blades, etc.

Tim

[Larry]

Three phase can come from the utility, phase converter, or variable frequency drive (VFD).  Normally utility three phase is too expensive for us hobby guys.

My shop built 10 HP rotary phase converter.




Used to power my three phase Oakley oscillating edge sander along with other machines.




You can buy one of these edge sanders new for $12,000 or you can pick one up at auction for $500, which is how I found my machine.

Mounted on the shop wall is a VFD which is used to power my three phase Delta 20" bandsaw.  The VFD gives me motor protection, variable speed, and braking.  All attributes also desirable on lathes, and sanders.

And where might one find this old, useless, and dangerous Wadkin?  I might be able to dispose of it properly.  Please send me a PM with the location. :D :D

[pineywoods]

Piston, I'm in the same situation. I recently acquired a 3 phase cabinet model table saw (delta unisaw)and a big industrial metal working lathe, also 3 phase. I have the materials and knowhow to build a phase converter, but there is another problem. 3 phase wiring is different from the normal 110/220 power. My shop is an old building with wiring close to 50 years old. I don't really want to re-wire it, so I'm thinking, just swap out the 3 phase motors for single phase. Started to mount a 2hp motor on the saw...oops it rotates in the wrong direction, so I'll have to tear into the wiring to reverse it. Probably will have the same problem on the lathe...always something  ;D

[Handy Andy]

  I'm not an electrician either, but have noticed you can buy 3 phase equipment much cheaper.  And if you check the new price, it is heavier, more expensive equipment than the single phase stuff most of us use.  Check ebay, they have the heavy 20" planers that sell new for 6000, pretty reasonable.  Of course, I don't know how much power it takes to run them.  I was at an auction, and one of these late model heavy planers brought 900.  No I didn't buy it.

[hackberry jake]

I have almost been bitten by the 3phase bug a few times. I still think about it from time to time. The power company charges you on how many amps you use. A 3hp motor on 120 will draw roughly 37 amps, on 220 (2 phase, electricians call it single phase still for some reason) the same motor would draw 17 amps. On three phase it would probably be close to 8 amps. But to my understanding, the rotary phase converters use a single phase motor to spin the three phase motor so you see no gain. I may be wrong

[Al_Smith]

Well it doesn't really work exactly like that .

What you are doing with a three phase motor as a phase converter is exactly that ,making the third phase by induction generation .Because of the inductive load the third or generated phase will have a slight lag with the other two and require some capactance to get it back in phase .

You start the thing by throwing a large capacative load across two windings of the motor which will give it rotation just like a start winding on a single phase motor .Once it's spinning it will climb up to running speed by itself with the removal of the large capacitor from the start circuit and make the third phase .

The rule of thumb for the amount of running capacitance the thing requires on a 240 volt circuit is 7.5 microfarads per HP .If it's over line voltage it's too high of capacitance ,too low too little but it doesn't have to be perfectly balanced .

Properly wired a convertor runs at around 92 percent efficient and will start up to the size of the HP rating of the conveter and run up to 3 times the size in HP of multiple motors .

To tell the truth I've lost count of how many I've built but time and again somebody always questions them which I guess is human nature .

To further add a 240 three phase motor will draw 2.5 amps per HP at full load across all three leads or 25 amps ..The same size converter will draw about 10 to 12 total but only on two leads because it's making the other phase and not producing anywhere near a loaded condition .So in spite of people saying you are paying for two motors you really are not .

Tell ya what it's a darn sight cheaper to either buy or build a converter as it is to replace a three phase motor with a single

  This is the last one I built which is now in Dowagiac Mich. running a ten HP punch press .

[hackberry jake]

Wholly cow, that's a lot of capacitance! I'd hate to get hit by that big boy!

[pineywoods]

I recently acquired a 3 phase 2 hp delta unisaw. Don't have 3 phase power available, so I looked at the options. I could build a rotary phase converter, but then I have to rewire the shop to accomodate 3 phase power. I already have a 3 hp single phase motor, so I opted to go that route. Turned out to be not quite so simple. Cobbled a motor mount (naturally different), only to find the single phase motor turned the wrong direction. Naturally, it's not reversable. I did manage to dig out the leads to the start winding and reversed them to solve that problem. Now I have a problem with the magnetic starter, won't work on single phase, no documentation, so I'm still facing a bunch more wire chasing...Hind sight, I probably should have just built the converter  :-[

[Al_Smith]

I can't think of any reason the magnetic starter would not work on single phase .Unless however it has a 240 volt coil that might have been used on a delta system which they did in some instances .

That big blue Mallory starting cap is 2000 MFD if I recall correctly .I'd imagine it would jolt a person .Those little oil filled caps are the runners at I think around 22 MFD each .The reason there's a stack of them is to allow for some leeway in case the sizing might be off .If I recall correctly not all of them are used .That thing is just stuff from my junk pile I had laying around .

[pineywoods]

Yeah Al, this thing was 3 phase delta 240 volt. Dang coil shouldn't know the difference between 220 and 240. I suspect the connections to activate the coil are tied to the now non-existent phase. Just a matter of chasing wires.. all packed in a small box right down on the base..

[Larry]

Check your coil voltage.  The voltage will be stenciled on the coil, but it may require dis-assembly to see it.  It could be 110 or I think some school shop machines were low voltage DC.

While your in there check the heater size to make sure it will be correct for a 3 hp single phase.

[pineywoods]

Thanks Larry. This saw did in fact come from a school shop. Had not thought about the coil voltage. Just assumed it would be 220/240 volt. If it's low voltage, there must be a small transformer somewhere, don't remember seeing one. Heaters may not even be there, if they are, I'll probably jumper around them. The replacement single phase motor is wired for 220 volts. I'll figure it all out when it warms up a bit. My shop is un-heated.

[Jason]

       Sorry to butt in on this post, Mr. Smith what do you charge for one of your phase converters? or how about some detailed info on building one? I have passed on some tools because of the 3 phase. I have a small one man operation looking to run probably not more than one 10 hp  3 phase tools at a time.

[upnort16]

I know from about 6 years ago when building the new shop the power company offered rebates, lower rates and ran three phase from the pole to building for free. We are located in town where three phase already exsisited is my guess as to why the power company did it. Certainly three phase equipment is on the used market and usually cheaper than single phase just for those reasons. We have since taken advantage and most all of our equipment is three phase. In an urban area it may be worth checking with power company, in a rural area, phase converters and or motor swaps. We have an old time electric motor repair shop in town. He has helped with motor swaps in the past at very reasonable prices. He also states with a larger converter its possible to operate more than one machine per converter. I quess I just wanted to share what I did, and to not dismiss having three phase brought in without a consult. Good luck.

[Al_Smith]

I won't build and ship them nor will I modify a chainsaw long distance .

Do a Google  search on rotary phase converters or homemade converters becuse there's tons of info on the net and it's fairly straight forward of how too .

The people who make converters of course caution people to deter them from building their own but remember they make a living manufacturing them so they want to keep you stupid .

It's just plain physics there is no magic involved . ;)

[Al_Smith]

As I was tossing another log on the fire a thought occured to me .Do a search for "home machinest " "practical machinest " or "Anvil fire " .

The first two forums deal with machine tools the later with metalurgy,blacksmithing and such .

Now just like this forum that might have  sawmills as the topic a side interest for operating same could be this rotary converter .Just like any forum there is a diverse crowd and they contain a lot of info and I do believe if memory serves me that this topic is fairly well covered .

If I get some time I've been wanting to make up a schematic of how to wire a converter but so far haven't got a round-tu-it .