3 Phase For Shop?

[Larry Caldwell]

I have a line on a milling machine that has two 3 hp. 3-phase motors. There is no 3-phase power to my property. I have a 400 amp 1-phase service split 200 amps to the house and 200 amps to the shop.

I'm looking at several solutions:

- Solid State phase converters. Expensive, and you lose 1/4 of the motor horsepower.

- Rotary converters. Even more expensive.

- 3-phase generators. My tractor would swing a 21kw generator head, if I could find one. A 15kw would do what I need. Unfortunately the milsurp generators all seem to be way bigger, a 15kw runs about $1k, plus frame, sheaves, belts, etc.

Or I could just see about replacing the motors with 1-phase motors. A single 50a circuit should run it, but the motor mounts are heavy castings and modifying them without cracking them would be tricky.

The last option is to pass on this one. That hurts, because the guy only wants $1000 for a big old 12" by 48" floor machine. But hey, farmer tools, ya know?

Anybody have any ideas? Sympathy?

 

[Tractor Seabee]

I have a line on a milling machine that has two 3 hp. 3-phase motors. There is no 3-phase power to my property. I have a 400 amp 1-phase service split 200 amps to the house and 200 amps to the shop.

I'm looking at several solutions:

- Solid State phase converters. Expensive, and you lose 1/4 of the motor horsepower.

- Rotary converters. Even more expensive.

- 3-phase generators. My tractor would swing a 21kw generator head, if I could find one. A 15kw would do what I need. Unfortunately the milsurp generators all seem to be way bigger, a 15kw runs about $1k, plus frame, sheaves, belts, etc.

Or I could just see about replacing the motors with 1-phase motors. A single 50a circuit should run it, but the motor mounts are heavy castings and modifying them without cracking them would be tricky.

The last option is to pass on this one. That hurts, because the guy only wants $1000 for a big old 12" by 48" floor machine. But hey, farmer tools, ya know?

Anybody have any ideas? Sympathy?

Set up a 3 winding 3 phase transformer as an open delta setup for just the motor. You feed it with single phase on the primary. There is some loss but increase size to compensate. Are you doing your own wiring? Google "open delta transformer wiring" and it will have a wiring diagram and the loss factor. A floor or wall mount you will have to make sure all the winding leads are available in the J box to accomplish it. If the motor is 460-480 you can boost the 240V up to the 460-480V. Power companies used to do this to provide 3 phase power in residential areas w/o 3 phase primary. No moving parts and economical.

Ron

 

[pmsmechanic]

This looks interesting.

 

[Larry Caldwell]

Set up a 3 winding 3 phase transformer as an open delta setup for just the motor. You feed it with single phase on the primary. There is some loss but increase size to compensate. Are you doing your own wiring? Google "open delta transformer wiring" and it will have a wiring diagram and the loss factor. A floor or wall mount you will have to make sure all the winding leads are available in the J box to accomplish it. If the motor is 460-480 you can boost the 240V up to the 460-480V. Power companies used to do this to provide 3 phase power in residential areas w/o 3 phase primary. No moving parts and economical.

Ron

Thanks for the info. It looks like it might serve the purpose.

 

[sandman2234]

I run my 2Hp Bridgeport on a little converter that was cheap when I got it. The power loss usually isn't noticed.
David from jax

 

[newbury]

I have a line on a milling machine that has two 3 hp. 3-phase motors. There is no 3-phase power to my property. I have a 400 amp 1-phase service split 200 amps to the house and 200 amps to the shop.

I'm looking at several solutions:

- Solid State phase converters. Expensive, and you lose 1/4 of the motor horsepower.

- Rotary converters. Even more expensive.

- 3-phase generators. My tractor would swing a 21kw generator head, if I could find one. A 15kw would do what I need. Unfortunately the milsurp generators all seem to be way bigger, a 15kw runs about $1k, plus frame, sheaves, belts, etc.

Or I could just see about replacing the motors with 1-phase motors. A single 50a circuit should run it, but the motor mounts are heavy castings and modifying them without cracking them would be tricky.

The last option is to pass on this one. That hurts, because the guy only wants $1000 for a big old 12" by 48" floor machine. But hey, farmer tools, ya know?

Anybody have any ideas? Sympathy?

There are several options, all viable. and a lot dependent on your respect for electricity.

I'm in a similar situation - I bought a little bit of 3 phase equipment for $800 years ago -

Mainly for the planer.

But have put off getting a power source, it seems I've always more important projects. So it sits in my shop and get's sprayed with Fluid Film occasionally.
My viable options are:
As Seabee wrote static is simplest, there are many you-tube vids of a guys with set ups they start with a rope, a belt, etc. But that always looks dangerous.
VFD (Variable-frequency drive) is another route and is dropping in price and with 3HP motors might be viable and safe. They used to be EXPENSIVE.
I'm trying to go the RPC (Rotary phase converter) route, I bought a 10HP 1760 RPM motor and a son is buying/scavenging the remaining parts (capacitor, enclosure, etc.). I mainly wanted the RPC because I have at least 6 different motors to run, which would require 6 VFD's. ( And would like to buy mor 3 phase.)

For your situation VFD's might be a sweet spot if you are only worried about 2 motors. Ebay sells a lot of good ones, and a lot of cheap ones, and from reports on Practical Machinist SOME cheap ones that are good. Just do your internet research and get good ones.

 

[sandman2234]

Anyone near Florida looking for a used 10hp motor to build a RPC with, let me know.
David from jax

 

[Mendonsy]

You can buy a 3hp VFD that will accept 230v single phase and output 3 phase in the $250 to $300 range. Two of those would probably be the easiest solution and would give you the additional benefit of having adjustable speeds for the motors.

 

[RNeumann]

I wouldn’t switch the motors to split phase. It introduces all sorts of other issues with speed control and replacement parts down the road. This video should provide some guidance. The big decision will be how much 3 phase do you want- just enough for this tool or loads of it for this and future tools (seems a lot of 3 phase tools come up used and fairly cheap!).

Static Phase Converters -vs- Rotary Phase Converters -vs- Variable Frequency Drives - YouTube

 

[mikester]

I have a line on a milling machine that has two 3 hp. 3-phase motors. There is no 3-phase power to my property. I have a 400 amp 1-phase service split 200 amps to the house and 200 amps to the shop.

I'm looking at several solutions:

- Solid State phase converters. Expensive, and you lose 1/4 of the motor horsepower.

- Rotary converters. Even more expensive.

- 3-phase generators. My tractor would swing a 21kw generator head, if I could find one. A 15kw would do what I need. Unfortunately the milsurp generators all seem to be way bigger, a 15kw runs about $1k, plus frame, sheaves, belts, etc.

Or I could just see about replacing the motors with 1-phase motors. A single 50a circuit should run it, but the motor mounts are heavy castings and modifying them without cracking them would be tricky.

The last option is to pass on this one. That hurts, because the guy only wants $1000 for a big old 12" by 48" floor machine. But hey, farmer tools, ya know?

Anybody have any ideas? Sympathy?

Im not sure about losing 1/4 of the rated motor HP on solid state units. Not an issue for me.

Ive been running one of these on my CNC for 10+ years with zero issues and I have no problem recommending them.
Phase Technologies - A world leader in low harmonic and phase converting technologies

This unit provides clean balanced power to the CNC which is susceptible to power problems. Ive never had any trip outs on this system due to dirty power or excessive THD. VFDs have been less robust in this situation.

Rotary units are noisy. VFD might work nicely for your situation as you have small motors. If you are looking at a manual mill Id suggest going VFD to start. If your mill has CNC or a lot of sensitive electronics then solid state is the only way to go.

 

[ericm979]

A lot of people with 1ph power get mills with 3ph motors so they can run a VFD for the speed control.

Sounds like a nice price for a large mill.

 

[Industrial Toys]

VFDs are great. I built a 10 hp rotary converter with much help from a friend to run a 600 volt 3phase lincoln MIG I bought by accident. Then I got a 600 volt drillpress/milling machine. It was a GIANT PITA starting and stopping that converter. Fine, if you are going to be using the tools for hours. The welder was the worst, plus the computer in the Lincoln never liked the fake phase.

Anyway, got rid of the welder and drill press. Still keep the converter, just in case. It also draws an insane number of amps on startup which is probably not allowed by the utility.

Some guy was here this week buying some old equipment from me and told me how the Utility Raped him in all manner of charges for 3 phase power, so he runs generators.

 

[Ortimber]

I installed a knee mill in my home shop and run it via a VFD. Works great and it’s a super simple solution.

 

[Sawyer Rob]

I have a rotary phase converter in my shop... Here's what it looks like,

Walk over, turn it on, and away it goes... After that, I can run my 3 phase tools, no problem at all, including several tools/motors at once...

SR

 

[Industrial Toys]

If you are using it for production, no problem. But to drill a few holes, on with the converter, off with the converter. And like I said, mocking up something on the welder was terrible, running on the phase converter. I do say, I miss that 3 phase brute.

 

[stuckmotor]

Someone sends us a letter several times a year asking if we have a third wire at the top of our power poles. They say the third wire signifies three phase. The people who send out the mailings say they want sites with three phase to establish solar power farms. It seems to me they could get that information from the power companies without sending out so many letters.

 

[Industrial Toys]

Well maybe not. I ask questions of the crews I see locally and know exactly where our power comes from, out fifty miles or so back to Bruce Nuclear. Where the transformer station is and such stuff. I have a friend who was doing some security stuff at Ontario Hydro, and post 911, such information is restricted. He could not get me that information.

 

[Larry Caldwell]

Thanks to those who recommended a VFD. I'll look into it.

 

[buickanddeere]

VFDs are great. I built a 10 hp rotary converter with much help from a friend to run a 600 volt 3phase lincoln MIG I bought by accident. Then I got a 600 volt drillpress/milling machine. It was a GIANT PITA starting and stopping that converter. Fine, if you are going to be using the tools for hours. The welder was the worst, plus the computer in the Lincoln never liked the fake phase.

Anyway, got rid of the welder and drill press. Still keep the converter, just in case. It also draws an insane number of amps on startup which is probably not allowed by the utility.

Some guy was here this week buying some old equipment from me and told me how the Utility Raped him in all manner of charges for 3 phase power, so he runs generators.

My Hobbart welder has terminals for 240V,480V and 600V. All single phase so all that is required to operate on 600V would be a transformer.

 

[buickanddeere]

Well maybe not. I ask questions of the crews I see locally and know exactly where our power comes from, out fifty miles or so back to Bruce Nuclear. Where the transformer station is and such stuff. I have a friend who was doing some security stuff at Ontario Hydro, and post 911, such information is restricted. He could not get me that information.

It isn't that complicated, the info is on the OPG web site. It goes more or less as the following. The Douglas Point Transformer Station is 52MW iirc from 230KV from the Bruce A Switch Yard down the 44KV. One 44KV line leaves the site and supplies the Bruce Energy Centre, Underwood, Port Elgin, Brucedale and South Hampton. The other 44Kv line supplies Inverhuron, Tiverton, Bervie, Armow, Kincardine, Pine River, Amberly, Point Clarke and Lurgan Beach. There are little substations here and there that drop the 44Kv to 2.3Kv,4160,7.2Kv, 13.8Kv and 27Kv depending of where what the loads are.
A old 230Kv line runs from the Bruce A site and joins a 115Kv at Owen Sound . Another 230Kv line leaves Bruce A into a new Wind Turbine Substation north of Underwood , can see it from Highway 21. iirc that line is the back feed from Hanover INTO the Bruce Site that powered most of the non generation buildings . Used to supply the Heavy Water Plant. A 3rd 230KV line heads east down the main power corridor between the 2nd and 4th concessions Has those d@mmed wind turbines on it too. . It turns to Bluevale and powers Lucknow, Wingham , Listowel and Teeswater. That same 230Kv carries onto Seaforth substation and powers Blyth, Clinton,Auburn, Goderich etc. . The 230 carries on and powers Grand Bend and then links to other 230 lines in a switchyard new Kitchener. Two of the 500KV Transmission lines go to Milton and other substations in that GTA area. A 3rd 500KV line swings south a few miles east of the plant and sort of meanders along to London, a cross to Nanticoke and up to Mississauga .
Just google " Hydro One distribution map "
Took almost a minute to find this link.Ontario’s Electricity System
Site Map
https://www.hydroone.com/businessservices_/generators_/Documents/honi_lsc.pdf