# 3-Phase Motor on DC



## Marleywood (Oct 15, 2016)

Hello!

New to the forum.

I recently bought the assets of a small woodworking business. One item in the lot is a JET DC system that has a 3-phase 220v motor. I am not going to have access to 3-phase 220 in my shop. I'm interested to see if anyone has any thoughts about how I can use the machine with standard 220v without breaking the bank doing so.

Replacing the motor with a single phase 220v (3hp) motor is an obvious solution, but to my mind, pretty much all this thing is is a motor that is used to create suction. Not to mention that I imagine this would be costly.

Appreciate any help.


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## GuitarPhotographer (Jun 26, 2015)

You can use a phase converter to get 3-ph out of single phase. They come as rotary and "VFD" varieties.


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## Steve Neul (Sep 2, 2011)

A phase converter can be an asset to your shop. Once you solve the three phase problem you will find out you can get some great old machines cheap that run on it. I bought a stroke sander one time off ebay thinking when I got it I would just change the motor. Once I got it I found out the motor wasn't replaceable at all so I ended up having to get a phase converter. Then I bought a 12" jointer, a 16" radial arm saw and a 24" planer and didn't have to give three phase a concern. I would recommend a VFD over a rotary phase converter. A rotary phase converter has a motor itself and unless you are using the machinery continuously you find yourself turning the converter on and off which is a bit of a pain.


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## Marleywood (Oct 15, 2016)

Thanks. I've been told about the Rotary Phase Converter, and also that I need another motor in line to start everything. This sound rather complicated (and a pain) to me. I was also told that a VFD was "over kill". Someone else said that some motors are "multi voltage" and that if I open an access plate and change the location of some wires inside, it might work, and that there was usually a diagram on the inside of this plate......Very confusing.

The motor is pretty big, I would think replacing it would be expensive too.


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## difalkner (Nov 27, 2011)

The motor is likely multi-voltage but not multi-phase; it's a 3 phase motor period. You can get a VFD off eBay relatively inexpensively. Take a look at the VFD's for CNC spindles and you'll find a slew of them available in the HP range you need.


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## Steve Neul (Sep 2, 2011)

Marleywood said:


> Thanks. I've been told about the Rotary Phase Converter, and also that I need another motor in line to start everything. This sound rather complicated (and a pain) to me. I was also told that a VFD was "over kill". Someone else said that some motors are "multi voltage" and that if I open an access plate and change the location of some wires inside, it might work, and that there was usually a diagram on the inside of this plate......Very confusing.
> 
> The motor is pretty big, I would think replacing it would be expensive too.


Single phase 120v is a single hot wire. Single phase 240v is two hot wires. Three phase 240v is three hot wires. It's considered 240v because it would read that on a meter if the meter was connected between any two wires. 

Three phase is different than multi voltage. An electric wire goes from positive to negative and back. Then on 220v you have two wires and when one is positive the other is negative. A 220v motor has two magnetic fields on the opposite side of the motor for the two wires taking turns firing turning the motor. Three phase has three magnetic fields in the motor so it comes down to more timing than voltage. It's like you took a two cylinder engine built a three cylinder engine and tried to use the two cylinder distributor cap. It wouldn't fire at the right time. 

If you took a three phase motor and used a single phase motor to get it turning it would continue to run on single phase 220. It would lack a lot of power and wouldn't run very good but it would run. Then if you wired a second three phase motor to it such as your machine both motors would run a lot better. The idler motor corrects the timing problem and generates the power for the third leg. The difference in doing this opposed to using an actual rotary phase converter is the phase converter uses capacitors which briefly bump up the voltage on one of the wires to 240 volts. This enables the phase converter to come closer to having actual three phase service. Otherwise the motor would lack the power it should have. 

A VFD on the other hand would give you three phase without having to run an idler motor. For occasional use the power would just be there as though you actually had three phase power in the building. We did have a member here which had a shop full of three phase equipment. He claimed he just turned his rotary phase converter on and just left it running until he quit in the evening. You would just have to decide what is best for you. Myself, I have the rotary and I'm thinking of wiring it to a remote clicker so I don't have to go across the shop and turn the thing on every time I want to run a machine.


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## Brian(J) (Feb 22, 2016)

Marleywood said:


> Hello!
> 
> New to the forum.
> 
> ...


I suspect swapping the motor for a single phase would be the least expensive route. Depends on what you can find on ebay or CL or where ever you look.
I just swapped a 1.5hp motor on my mill to VFD and 3 phase in order to get the variable speed and it's great but would never have done that to a DC. I paid $170 for a AutomationDirect GS2-22P0, that's a 2hp model. If you decide to go VFD consider the programming which can be quite a chore, I went for a AutomationDirect VFD because the programming is very easy. 
I bet you could find a motor for $100 to $150 and a lot less work to set up.


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## woodnthings (Jan 24, 2009)

*replace the motor*



Marleywood said:


> Hello!
> 
> New to the forum.
> 
> ...


If the motor drives a centrifugal blower it probably has a face mount for the housing and a frame mount for motor, type "56 C" if I'm remembering correctly. The shaft diameter is also a factor or the blower will not mate, and reducers will be needed IF you can find a suitable single phase motor...?

Grizzly has one on this list and there are others... not breaking the bank either. :wink2:

http://www.ebay.com/sch/i.html?_fro...e+motor.TRS0&_nkw=3+hp+3+phase+motor&_sacat=0


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