3 phase to single phase

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I'm looking at lathes right now and would like to get one when I find a decent deal.  A lot of the ones I find are 3 phase which I do not have in my garage.  Has anyone converted a 3 phase tool to single phase?  What is the best way to do this, a new motor or phase converter?  It would be nice to be able to consider 3 phase lathes also in my search but would need to know what the cost is going to be to change it over to single phase.  Thanks for any advice on this, Scott
Reply:Wanted to put this in the machine forum but accidently posted it here.  If a moderater sees this can you please move it for me.  Thanks
Reply:I bought a 3 phase lathe. I found out after I bought it what my options were.1. VFD 2. RPC3. Static Phase Converter4. Change out the 3 phase for a single phase motor.I went with the VFD option. I found a good TECO FM100 VFD for either $50 or $100 I forget. It takes 220 single phase and converts it to 3 phase. The VFD gives you tons of options to control the 3 phase motor you are running. You have variable speed, ramp up and shut down delay...just lots of options.A rotary phase convertor can be built with a 3 phase motor as long as its larger than the tool motor that you want to power. There are lots of webpages available where people have made their own. I have a 7.5 horse motor that is sitting on my garage floor waiting to be turned into a RPC. I have the start capacitors but need the run capacitors and some switches.I heard that static phase converter are not that great. I don't have any experience with them.I didn't have a single phase motor lying around to switch out my 3 phase motor and didn't feel like rewiring my lathe.That's my experience with running a 3 phase motor. There are probably other options but that is what I found out when I was looking at getting my lathe running. The practical machinist website has a section just for VFD's and RPC's
Reply:Originally Posted by shanghydI bought a 3 phase lathe. I found out after I bought it what my options were.1. VFD 2. RPC3. Static Phase Converter4. Change out the 3 phase for a single phase motor.I went with the VFD option. I found a good TECO FM100 VFD for either $50 or $100 I forget. It takes 220 single phase and converts it to 3 phase. The VFD gives you tons of options to control the 3 phase motor you are running. You have variable speed, ramp up and shut down delay...just lots of options.A rotary phase convertor can be built with a 3 phase motor as long as its larger than the tool motor that you want to power. There are lots of webpages available where people have made their own. I have a 7.5 horse motor that is sitting on my garage floor waiting to be turned into a RPC. I have the start capacitors but need the run capacitors and some switches.I heard that static phase converter are not that great. I don't have any experience with them.I didn't have a single phase motor lying around to switch out my 3 phase motor and didn't feel like rewiring my lathe.That's my experience with running a 3 phase motor. There are probably other options but that is what I found out when I was looking at getting my lathe running. The practical machinist website has a section just for VFD's and RPC's
Reply:VFD's are cool and a guy down the road runs all his 3phase stuff with them.  I went with a rotary converter with a 20hp motor.  I ran a 50 ton Iron worker off it and my lathe.  I sold the iron worker and just run the lathe now but I could buy some large equipment now and have no worries running it.   A VFD is only good for running motors.  It will not run welders etc.  A rotary can pretty much run anything and work when motor braking is required etc.  I think for a lathe a VFD would be a good choice.
Reply:My VFD runs off the dryer plug and the breaker that was installed for the dryer.I install the 220V wires on the left of the VFD and the 3phase wires on the right side of the VFD.I'm putting together the RPC as an expirement.
Reply:You can add large capacitors to the third leg and it will run on single phase. You will also need a temporary starting capacitor to get the thing moving, once running switch the starting cap out and it runs fine. I have done this for up to 5HP with no problems. There is a formula for what size capacitors you need but I don't have it any longer. You need the big capacitors that are in air conditioner units.WeldPro LS160PForce Cut LP80D
Reply:Originally Posted by GadgetThere is a formula for what size capacitors you need but I don't have it any longer.
Reply:Originally Posted by GadgetYou can add large capacitors to the third leg and it will run on single phase. You will also need a temporary starting capacitor to get the thing moving, once running switch the starting cap out and it runs fine. I have done this for up to 5HP with no problems. There is a formula for what size capacitors you need but I don't have it any longer. You need the big capacitors that are in air conditioner units.
Reply:Oh yeah, the bad side of PM is that they're rough on newbies. They're pretty harsh over there unless you ease in to it.HomeShopMachinist (at http://bbs.homeshopmachinist.net/ ) is a little easier on noobs, but I just don't like their forum layout (they really need to separate the off topic from technical section). I find it annoying to see political posts and funny pictures next to technical questions.The soldering toys pay for the welding toys.Hakko 928 dual iron, 4xHakko 936Madell 850D Hot Air SMT ReworkMiller 252, HTP Invertig 201 AC/DC, and a Hypertherm 45.
Reply:Originally Posted by cabletechOh yeah, the bad side of PM is that they're rough on newbies. They're pretty harsh over there unless you ease in to it.HomeShopMachinist (at http://bbs.homeshopmachinist.net/ ) is a little easier on noobs, but I just don't like their forum layout (they really need to separate the off topic from technical section). I find it annoying to see political posts and funny pictures next to technical questions.
Reply:You can use Google to search. For example, go to Google, and type in:site:practicalmachinist.com +3hp +VFD +connectionThat limits the site to PM, and the + will force Google to find posts with only those terms. Works well on sites that have searches that suck. The soldering toys pay for the welding toys.Hakko 928 dual iron, 4xHakko 936Madell 850D Hot Air SMT ReworkMiller 252, HTP Invertig 201 AC/DC, and a Hypertherm 45.
Reply:Originally Posted by cabletechYou can use Google to search. For example, go to Google, and type in:site:practicalmachinist.com +3hp +VFD +connectionThat limits the site to PM, and the + will force Google to find posts with only those terms. Works well on sites that have searches that suck.
Reply:I did a quick search on this site and found a page full of threads about phase converters; one I remember 'cause I added to it is here:http://weldingweb.com/vbb/showthread.php...ase+converters
Reply:I like this page.http://home.att.net/~waterfront-wood...econverter.htm
Reply:I just recently converted a  5hp Curtis air compressor with a 3 phase motor that I purchased for a really good price at a auction, to single phase, found a great deal on a new 1 phase Baldor 5hp motor & motor starter, easy to change over & total cost of the conversion was aprox 450 including the new motor (Free shipping) and motor starter. I looked into the other possibilities, VFD, etc, but they only seemed economical up to 3hp,  in the long run this seemed like the best overall solution for my needs.The conversion process was simple & strait forward, & wiring was a breeze. If your looking for a good deal on a new single phase motor try here: http://stores.shop.ebay.com/WECO-GRO...34Q2ec0Q2em322or here:http://www.electricmotorsite.com/Last edited by Crazy Horse; 09-18-2009 at 08:09 PM.
Reply:Originally Posted by Crazy HorseI just recently converted a  5hp Curtis air compressor with a 3 phase motor that I purchased for a really good price at a auction, to single phase, found a great deal on a new 1 phase Baldor 5hp motor & motor starter, easy to change over & total cost of the conversion was aprox 450. . .The conversion process was simple & strait forward, & wiring was a breeze. . . .]
Reply:Thanks for the welcome, As for my compressor conversion details as follows: Compressor is a 2 stage Curtis 5HP 80 gal vertical Challenger series with the E57 pump, rated at 18.1 CFM @ 175PSI.The motor on the compressor was a  Baldor - 3ph - 5hp - O.D.P. - 1750rpm motor, Frame size 184T. Baldor makes several 1ph -  5hp - 1725rpm - O.D.P motors with the same frame size 184T (mounts, shaft, pulley size, all match old motor, also belt length & guard all match as well.)  I purchased a Baldor L1410T - 1ph - 5hp - 1725rpm motor , FLA is 23A & has plenty of starting & running torque. The motor is heavy duty & heavy as well, weighs 86lbs !Motor starter is a single phase Siemens with a 40A contractor 220-240VAC Coil w/1 aux. N.O contact & single overload relay with bi-metal heater rated for FLA x service factor of 1.15. As an added bonus I got a great in depth education into compressors as well. In the near future I will touch the paint a bit on it, but for aprox $1100 I have all the compressor I will ever need.I really like the VFD route, but at 5hp it seemed was more cost effective to go the route I went Speaking of another compressor, I also picked up a Speedaire 5HP 80 gal 2 stage horizontal compressor, in real good condition just missing the motor at the same auction & plan to convert it as well & sell it to fund a plasma cutter !Last edited by Crazy Horse; 09-18-2009 at 10:32 PM.