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Running 3 phase equipment at home?

C

canucktruck

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Jul 21, 2009
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Ontario, Canada
A friend of mine bought a milling machine and lathe for his home shop and they are both 3 phase 220. He wants to build a convertor to run them at home off single phase 220. I looked at a similar machine that came with a Rotophase convertor and it seems like the convertor is like an electric motor to change the single phase to 3 phase.

Does anyone have any information or "how to's" on making this convertor, what's required etc? We will be working with an electrician to do the project but he's not exactly sure how to do it.

Also are there any prblems with this type of system or does it run just as well

Any help greatly appreciated
 
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onewaydave

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Down the road from Dorothy and Toto
You can get 3 phase from the electric company. $$$$
You can make/buy a static converter, using solid state circuitry. $
You can build/buy a rotary converter, using a 3 phase motor, capacitors, and circuitry. $
You can use a VFD to run a 3 phase device off of single phase 220v. This will run about 250-300 depending on the amps the motor draws (i think). $$ but gives variable speed for mills and lathes without other devices.

Dave.

The practical machinist website has a lot of info on all of the above.
 
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wyliesdiesels

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Modesto, CA
**** in Wisconsin said:
Has he asked the power company what a three phase service would cost? It might be in the neighborhood and not too expensive to install.
Click to expand...

A 3-phase power installation can be expensive and if you're someone like the OP who may only have a few 3-phase machines, the cost may not be worth it! A VFD or rotary converter is usually a more cost effective solution!
 
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Jeep07

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Jan 1, 2008
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I use a 20hp American rotary phase converter. Expensive but runs anything 3 phase I need at full power.

Sent from my SCH-I535 using Tapatalk 2
 
N

Norcal

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onewaydave said:
You can get 3 phase from the electric company. $$$$
You can make/buy a static converter, using solid state circuitry. $
You can build/buy a rotary converter, using a 3 phase motor, capacitors, and circuitry. $
You can use a VFD to run a 3 phase device off of single phase 220v. This will run about 250-300 depending on the amps the motor draws (i think). $$ but gives variable speed for mills and lathes without other devices.

Dave.

The practical machinist website has a lot of info on all of the above.
Click to expand...

A static converter is a bad idea, all they do is start a 3Ø motor, then drops out & single phases the motor this is not ideal, & there is a 1/3 loss of HP.

Single phase input, 1 HP & less VFD's can be bought w/ a 120V OR 240V input, above that it's 240V only up to 3 HP, above 3HP then a 3Ø input VFD that can have the phase loss parameter changed, & then they usually are derated 50%, namely a 5HP motor would require a 10HP drive.

Here is a link to the PM forum.

http://www.practicalmachinist.com/vb/transformers-phase-converters-vfd/
 
S

Sureshot

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Bridge Creek, OK
I run my 3 phase lathe on a static inverter and it runs fine. A good number of oilwells around the country also run on them. I actually have a spare or I could get you the name of a supplier here who builds them. PM if interested.
 
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Falcon67

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I run my 1 HP 3 phase mill/drill with a VFD. Love it. When I finally get a 12x36 or so lathe, I'd convert it to 3 phase and buy another VFD. I just like how they work and the programmability of functions.
G0519.jpg
 
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HoosierBuddy

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Southern Indiana
I'm running my lathe off of a VFD. The speed control is sweet, but I have heard some people say you can burn up an old motor that way (running a 60HZ motor at 20HZ for example). I haven't had any trouble...yet, but I do try to keep my VFD at 60HZ unless there's some specific reason I need to run it lower or higher.

The other option no one mentioned would be to replace the motor with a single phase motor. My milling machine has a single phase motor for example that can be wired for either 110V or 220V operation.

My limited understanding is that 3 phase motors are more cost effective to operate compared to single phase. That's why a lot of (or most) industrial equipment was equipped with 3 phase motors. However, for home shop use, you just aren't going to have that much cost for power anyway.

Phil
 
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K

kazlx

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Oct 30, 2012
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Location
Tustin, CA
I have ran equipment on a VFD and a rotary phase converter (RPC). VFD's are easy, you just buy one for ~$100 per machine, install and turn it on. You need to make sure that you use the VFD to run the equipment though and don't have any switches installed after the VFD. The wires from the VFD go directly to the motor you are powering.

RPCs are anywhere from simple to complicated. I built a basic one using a 5hp motor and an industrial cutoff switch. How it basically works is you use your single phase to run a 3 phase motor. That 3 phase motor then essentially becomes a generator to create the third phase. Single phase power will not start a 3 phase motor, but it will run it.

So you have a few options: 1) hand start with a rope or something to get it spinning, then hit the 220V juice and it will stay under power, 2) use a 110V pony motor with a switch where you basically connect the two with a belt, start the 110V motor, let it come up to speed, then switch on the 3ph motor, or 3) built a remote starter setup using capacitors to basically store enough juice to 'jump start' the 3ph motor. This can also be use to 'balance' the 3 legs of the motor to get 'cleaner' power.

For an RPC, you just hook up your machine to the RPC and it will run just like it would in a 3 phase shop. You can also run multiple machines off the same RPC if you size it right. There are also guys that run large RPCs and basically generate enough 3 phase power for their entire shop. You can also build a small RPC with a long cord and plug it to the machine you want to work on or a small cart where you can roll it around.
 
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Falcon67

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My 2HP was about $175, but that was about 4 years ago. I leave mine at 60hz unless I have some special need. Experimentation showed that my machine motor doesn't mind too much +/- 20 hz. Get to around 30~40 hz off and it begins to complain.
 
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