Putting the cart before the horse…..Three Phase power question???????

[Runs With Scissors]

OK fellas, I finally “stepped up to the plate” and bought a Bridgeport. I still have to get it in the basement, but when I do, I have to power it; So I am trying to “think ahead” a little and formulate a “plan of attack”.



Like most people, I obviously have single phase power, so I am going to have to “make my own” 3 phase power to run it.

I have done some initial investigating on my options, which I believe to be the following.

A) Use a Digital Phase converter.

B) Use a Variable Frequency Drive.

C) Use a single phase, 220 volt motor to turn a 3 phase motor, thus creating “actual” 3 phase power.


I have some “very basic” understandings of these options, but would like some opinions/reasons from y’all.



I am curreently leaning towards a VFD.

My reasoning is that a VFD will allow for ‘speed control”; So I can put the machine in “fast gear” and control the motor speed (i.e. slow it down) with the VFD, and they seem very reasonably priced.

My current understanding is that a Digital Phase Converter will not allow for “speed control” , and option “C” seems unnecessarily complicated, and expensive, and will also not allow for “speed control".


Is my reasoning sound?

I am open to other suggestions/ideas/options as well.

 

[WI_Hedgehog]

There is different wiring for industrial 3-phase, Wye (likely in your application) and Delta. You might verify what you have first, I've seen some funky things...

 

[ken erickson]

I ran a 1HP step pulley Bridgeport mill for a decade with a static phase converter in my Gunsmithing business with good results. My understanding is you will lose about 1/3 of the rated horse power. For my work at the time not an issue.

I currently have a static phase converter on my Harig Super 6-12 surface grinder with equally good results.

I have 3 VFD single phase converters running various knife making grinders. Two 2 x 72 belt grinders and a 8 inch disk grinder.

I WISH I would have had a VFD on the Bridgeport.

 

[Bee-Positive]

Check the motor specs that comes with the unit. Do a search on "VFD motor compatibility".

Read this...

VFD Compatibility: Can I Use A VFD With Any AC Motor? Key Considerations Explained [Updated: November 2025]

A Variable Frequency Drive (VFD) can control many AC motors, including induction and synchronous motors. However, it may struggle with induction motors that

motorsandpump.com

or this

Can Any Electric Motor Run on a VFD? An Engineer's Perspective | Vanco Electrical Solutions

The versatility of Variable Frequency Drives (VFDs) has made them indispensable in modern industrial applications.

vancoelectrical.com

 

[LFP57]

Do some searches on running a DC motor with speed controller, one part of the project was to create adapter plate which you should not have any problem creating.
Building a DC Drive for the Bridgeport Spindle

 

[Russell King]

Notice that @ken erickson says “3 VFD single phase converters” to get from single phase to shift the phases 120 degrees from each other. I think the converters must be able to communicate with each other to know what they are doing. That might mean they all need to be same brand?

I would recommend the VFD route.

 

[ken erickson]

Notice that @ken erickson says “3 VFD single phase converters” to get from single phase to shift the phases 120 degrees from each other. I think the converters must be able to communicate with each other to know what they are doing. That might mean they all need to be same brand?

I would recommend the VFD route.

Sorry guys! My statement "3 VFD single phase converters" is clear as mud.

Besides my static phase converter running the surface grinder with 3 phase motor I should have said I have 3 single phase VFD's running my grinders which are all single phase machines.

 

[Kennyd4110]

VFD...100%.
The variable speed and programmability is worth it.

I have three 3PH machines (Bridgeport mill, Clausing lathe, and a 2x72 belt grinder) and I use the VFD features on each one.

 

[Russell King]

Sorry guys! My statement "3 VFD single phase converters" is clear as mud.

Besides my static phase converter running the surface grinder with 3 phase motor I should have said I have 3 single phase VFD's running my grinders which are all single phase machines.

Sorry for my misunderstanding of your comment and my lack of understanding about the VFDs creation of the third phase.

Here is a link to a VFD being used on a Bridgeport mill so presumably pretty close to what @Runs With Scissors is thinking.

This is another discussion about the subject in general

Can a VFD Convert Single-Phase Power to Three-Phase?

Using VFDs To Convert Single-Phase To Three-Phase One of the most common calls we receive at VFDs.com is asking about phase conversion: Can a Variable Frequency Drive (VFD) convert my single-phase power supply to run a three-phase motor? Many who call us are looking at the ability to combine...

vfds.com

 

[Hugo Habicht]

I had the same problem with my lathe. The motor was wired for 400V three phase star configuration and I changed that to delta, making it 230V three phase. I use Toshiba inverters for the conversion from single phase 230V to 230V three phase. I am not using variable frequency but only the soft start (programmable) that I also use on the hydraulic pump of the pillar lift. I simply have the on/off function and the speed change is using the various gears.