3 Phase Machine

Believer · December 22, 2009, 07:30:24 PM

I'm doing some long range planning. By the way, this is my first post and I know I'll learn alot here. Anyway, I want to build my own timberframe home. I'll practice on some smaller structures first. I'm thinking through the equipment I'll need including a planer moulder for interior flooring, trim, casings, ceilings, etc. My property only has single phase power but I've read some posts not to be afraid of buying three phase equipment. Can someone fill me in in on how to adapt three phase equipment to single phase power? Should I really be considering doing this? It seems there's better equipment on the used market in three phase. Thanks in advance.

Dave Shepard · December 22, 2009, 07:31:53 PM

To run 3 phase on single phase service requires a phase converter. Rotary is better than static. Welcome to the Forum!

Kelvin · December 22, 2009, 08:26:14 PM

You can google making a rotary phase converter. It can be pretty simple to do if you have any electrical knowledge at all. Even if you buy one, or better yet a used one, or buy a static converter and hook it up to an old 3 phase motor 50% bigger than any motor you plan to start with it you can put one together and not need to know all about how they work.

However you can hire out most of the work you are thinking of doing, and be further ahead, unless you will have reasons to have the equipment after you are done with your house. Lots to learn between buying and hooking them up and making them run properly. Especially old commercial machines.

good luck. I built my own timber framed house with help from my friends and only one of us had a little experience of having been to a week long workshop. Its pretty easy to do the framing. Harder to make all the stuff match the framing.

Good luck with your project. Lots of advice to lookup here.
KP

fishpharmer · December 22, 2009, 08:34:31 PM

Believer, welcome to the forum. Good question, I have noticed alot of nice used 3 phase woodworking equipment, converting single to 3 phase would sure help.

Magicman · December 22, 2009, 09:33:29 PM

First Believer....Welcome to FF. Contact your power company and get an answer from them before making an investment. It could be simpler.....or more complicated than you think. Good luck...... 8)

James P. · December 22, 2009, 09:42:10 PM

Believer,
Welcome to the forum, if you do buy 3 phase just make sure it is 220 440 . some of the older industrial machines were only 440 which complicates things. I run a few 3ph machines. I have a 1hp bench grinder 3ph that I have a capacitor running off 1 of the 220 hot legs.basical teed off. It creates my 3rd leg. All other 3ph motors are wired to the same 3 legs using motor starters in between. I just turn on my grinder and then turn on the smaller or equal size motor. Kelvin is right about sizing it to be 2x the size of your largest motor to be run.. It works but can draw alot more starting amperage using the right size capacitors is crucial and that depends on the motor you are using for a rotary converter. some types of windings are better for the rotary motor as well. be careful capacitors hold juice even after they are disconnected from power. they have to be shorted to discharge. Good luck

red oaks lumber · December 22, 2009, 10:24:40 PM

when i first started, i used a generator to run 3 phase later spent the money on bringing in 3 phase power.. just another option to throw at you. welcome to the forum!!

Ironwood · December 23, 2009, 12:01:04 AM

Magic,

Sorry, calling the power co. is the WRONG thing to do. The quote you get to even run a service down from a pole w/ three phase on it will make your head spin$$$$. Just get a generous service panel, 150 amp or better and hook up your converter. Telling the power folks anything, in some areas they could automatically bump your rates to a demand meter. They dont need to know what you do inside YOUR place, just get them to set a pole a hire your electrician to put in a panel. FYI, if you make a three phase sub panel the breakers are $$$ expensive. We have TONS of country folks in these parts running all sorts of three phase converters. Dont pass up the good stuff, and as stated look for 220, 440 only can be rewound but is more costly. I have had some screaming bargins rewound, just depends on how good you are "IN" with the local motor shop.

Ironwood

logwalker · December 23, 2009, 01:23:10 AM

I was able to buy all my breakers and a nice Westinghouse 3 phase panel for not too much off of ebay. My converter came off Craigslist. A commercial 20hp for $500. I run my 15 woodmizer with out a problem. If you stay at home it is the best way by far. I just bought a Northfield #4 tablesaw for $250 in perfect running condition. I also got a Whitney double spindle shaper and frequency changer last January for $150. I have many other 3 phase machines. It will cost a little more to set up but right now the machines are scrapeing bottom. That Northfield saw I mentioned sells new for $12,960. That is not a misprint. And the magnetic starter for it is another $1200. You guys on the east coast have an almost unlimited opportunity right now to pick this equipment up. We hardly have any out here and I still manage to find some. Good luck with your project. Joe

Bibbyman · December 23, 2009, 02:11:23 AM

Welcome to the Forum.

Here is a link to the little know knowlege base where I have posted how we we set up our roto phase converter.

https://forestryforum.com/tips/tips.cgi?display:1048263552-19768.txt

kelLOGg · December 23, 2009, 05:37:43 AM

I run only a 5 HP planer on 3 ph so I built my own from the link below. For the idler motor I bought a 7.5 HP 3 ph on ebay and a bunch of capacitors from Surplus Center. Probably spent less the $150 for all and most of that was shipping.
I enjoyed making mine and I hope you do too.

Bob

http://home.att.net/~waterfront-woods/Articles/phaseconverter.htm

Magicman · December 23, 2009, 08:46:11 AM

Quote from: Ironwood on December 23, 2009, 12:01:04 AM
Magic, Sorry, calling the power co. is the WRONG thing to do. Ironwood

Thankfully you and I are served by different power companies..... :D

DanG · December 23, 2009, 09:14:12 AM

Yes, the power company makes a lot of difference. Our REA co-op is real gentle on 3-phase, and farmers get a huge discount to boot. Unfortunately, it doesn't come down my road though. I don't know what it would cost to extend it another 2 miles.

James P. · December 23, 2009, 09:23:29 AM

Logwalker, you've got to be kidding. Every time I see something going cheap on the online auctions its on the west coast. Oregon state surplus and Boeing.You've got it made. I think there may be more here but there is alot more demand. I wish sometimes I could afford to ship a big load of machine back this way. then I realize I have enough problems paying for what I have and it usually stops my drooling .
Magicman, it really depends where the nearest 3 phase power lines are. If its just putting up a new transformer on your existing pole it may be worth discussing with them. If they have to bring it from a mile or 2 away. They will either just say no or give you an estimate that will make you say no. Some things just can't be done efficiently thru phase converters and actually getting 3ph service or a properly sized generator is the only option.

Stan snider · December 23, 2009, 10:22:51 AM

DanG; I checked on the three phase and the third wire cost $12.000 per mile several years ago. That will set your ambition back on it's heels. Most rural service lines are looped to feed from either end and if your connections with the engineering department are good you can get a feed from two directions and have the third leg that way. I couldn't get it to work for me but a friend did. I built a convertor and am about to build a larger one. Stan

T Red · December 23, 2009, 01:51:07 PM

You do need to be sure the voltage and phase configuration is the same for all your equipment. In most areas 120/208 Y is standard. It is nice because you can pull 120 volts to neutral off of any leg.

However there are areas of the country that use a 120/240 volt Delta. It has 2 legs at 120 volts and a high leg at 208 volts to neutral. You just have to watch where you put that single phase load.

CLL · December 23, 2009, 04:22:17 PM

Local electric company here wanted $20,000 to run 3 phase less than 1/2 mile, plus you have to pay at least $350 for a minimum of two years. NOT!!!!!!!!!!!!!!!!

ronwood · December 23, 2009, 06:29:01 PM

I was really lucky. The local coop installed 3 phase 240 v 200 amp. With trench and materials it cost me around $1000.00. Had main feeder line running in front of my property sothat help a lot.

Ironwood · December 23, 2009, 07:06:09 PM

Here in Pa., even if you had it at the pole you would NOT want it. "Monthly minimums" are in the $400-500 range. This at current subsidized cost, once that contract is up (soon), I would not want that BILL!! They want commercial / industrial users and make sure to scare everyone else away. I have had afew friends who trusted someones word (not in writing) and had 3 phase hooked up and then their monthly minimum bill showed up

.

Ironwood

shinnlinger · December 23, 2009, 07:52:35 PM

I have heard there is a newer option to convert, VFD(VARIABLE FREQUENCY DRIVE). You only need to to buy one for all your three phase stuff that is in the same power range (that is true for rotary or static converters as well) You can only run one piece of equipment at a time, but for a one man show that is usually OK.

Al_Smith · December 25, 2009, 07:33:05 AM

A "static " convertor they sell is merely a start circuit for a 3 phase motor and will only produce about 57 percent of the motors name plate rating .In other words slightly less than 6 HP from a 10 HP motor .

A properly built rotary converter runs at around 93 percent efficiency and will start up to the HP rating of the motor used for the convertor .For example a 10 HP will start another 10 HP but will run up to 3 times that amount .

I've lost count how many convertors I've built but some where around 20-25 I suppose . The last one is residing in Dowagiac Mich running a punch press .

A lot of people are under the misconception you are paying for the price of running two motors ,not so . Fully loaded a 10 HP motor at 240 volts 3 phase will draw 25 amps or 2.5 amps per HP . The wattage is 240 times 25 times 1.73 on 3 phase .

The same motor on a convertor would be 240 volts times 25 amps and because there is no 3 phase the 1.73 does not enter into the formula .The third phase is produced by the convertor often called the pony and that thing will draw about 10 amps once running no matter what load is on it .--Magic --- ;)

Al_Smith · December 25, 2009, 07:43:56 AM

Another thing .If the thing is a straight 480 volt motor ,no big deal .Several ways to skin that cat .The easiest is to run the converter output to a three phase 240 to 480 transformer wired up backwards--240 in ,480 out .The transformer really doesn't care which is line voltage and which is load it works both ways .

My personal convertor in my shop is a 5 HP 480 volt motor using two single phase transformers back wired 120 in 480 out or 240 across the windings hooked in series with the outputs in parrellel . Then a portion goes to a 10 kva 480 to 240 transformer plus some other rocket science crazy Ohio hillbilly rigens to get 208/365Y Europian 3 phase plus 277 single phase . Shucks if I had enough transformers I could make a bolt of lightning . :D

Ironwood · December 25, 2009, 09:30:31 AM

Al,

Thanks for the input, and while I did NOT follow all the hillbilly hicky jigger stuff, your story of how many you have built shows others how easy it can be (Al is no rocket scientist :D, just kidding AL).

It REALLY is no big deal, you should see some of the "farmyard" converters in my area. :D. Mine is a little more involved (automated) but, " it dont take much to make one".

Ironwood

Al_Smith · December 25, 2009, 10:02:29 AM

I've seen some hillbilly convertors that are crude as a fence post that worked,not real well though . Just a motor they literally rope started .Some use a single phase motor to turn them over .All kinds of silly stuff .

Mine are a relay to pull in the start cap which is a big old electrolytic 1500-2000 Mfd deal and 7.5 MFd per HP oil filled run caps .All started from a push button ,No rope for old Al .

By getting the right sized run caps you can balance the output within a few volts .Too large you run over voltage ,too small under voltage .

I suppose if a guy really wanted to be a wizard you could use a current relay to step in or out added capacitance .Bear in mind though that a home built convertor or store bought for that matter is not a nuke power house .Close enough is close enough .

Al_Smith · December 25, 2009, 10:11:30 AM

Let me use another thought on this .The same start circuit used on a convertor can be used on any three phase motor . The problem like I said is you only get 57 percent power out of them but you are only paying for that amount too .

If you don't use run capacitors the motor will over heat because of the induction on the unused winding of the motor so keep that in mind .Further more either use the motor as a motor or a pony motor .It won't do both at the same time or at least not very well or very long .Once all the smoke leaks out they never run again .