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Anyone using a VFD / Phase converter to run your 3 PH equipment?


GunCat
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I’ve e been using a static phase converter to run a 220V 3PH lathe for years. No problem with that. Now I have another Bridgeport mill to hook up and I am learning that we now have Variable Frequency Drives that not only let you adjust the motor speed (within certain parameters) but these VFDs will also act as phase converters AND (this is the parts that blows my mind) will produce 220V 3PH output from 110V 1PH input.

Assuming you use the correct size VFD (in my case a 1HP motor on the Bridgeport) are there any downsides to using this 110V 1PH in / 220 3PH out device?

(It all sounds too good to be true)

Edited by GunCat
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Depending on the age of the motor, a VFD can be harmful to the windings. Most new motors and quality older motors will be ok for VFD use.

Technology is some times a good thing. Just don't expect a VFD to last forever. Depending on abuse/use they could break very quickly. Buy a spare if its a critical machine.

Most of the time they will have to be setup for your specific installation. If your not familiar with control systems, seek advise.

Good luck.

Edited by CB45
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While it is possible to change single phase 120 into 3 phase 220 remember the power out of the VFD will be less than the power in. (The first two laws of thermodynamics - you can't win (matter (energy) can not be created nor destroyed, only changed in form) meaning you can never get more out than you put in, you can't break even (all processes will have some loss).

(Highest efficiency I have seen on a VFD is about 80%).

What I am saying is for a 3 HP motor you may be drawing a lot of current on a single phase source.

(3 hp = 34 amps on 115 single phase or ~2200 watts. 3 phase motor at 230 v is 9.6 amps still ~2200 watts. So at 80% efficiency the draw on 115 v is about 43 amps.

For a 1HP = 16 amps on 115 single phase or ~745 watts, 3 phase 230 is 3.6 amps (still ~745 watts) 80% efficiency 115 v single phase is about 20 amps).

(Added approximate draw in amps)

Edited by GuildSF4
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I am running a series 1 bridgeport on a VFD. I am not a heavy user, but it has worked great for me and was a very inexpensive option. I studied the book before start up and was able to easily hook up a direction switch and a small pot for speed control.

Sherwyn

I’ve e been using a static phase converter to run a 220V 3PH lathe for years. No problem with that. Now I have another Bridgeport mill to hook up and I am learning that we now have Variable Frequency Drives that not only let you adjust the motor speed (within certain parameters) but these VFDs will also act as phase converters AND (this is the parts that blows my mind) will produce 220V 3PH output from 110V 1PH input.

Assuming you use the correct size VFD (in my case a 1HP motor on the Bridgeport) are there any downsides to using this 110V 1PH in / 220 3PH out device?

(It all sounds too good to be true)

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I'm also running my series 1 Bridgeport, 1 hp on a VFD. I got one good for up to 3 hp motor and didn't cost much more than a unit rated for 1 hp.

Had to call the manufactures tech line for help to hook up. Tech got me going and unit was easy to hookup. My VFD is using 220V single phase to 220V 3ph.

Added some plugs between machine and VFD so I can switch to lathe. Takes less than a minute to switch between machines. Can't run both at same time but can run both off the same VFD.

Been running for just over a year and am very happy.

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I install alot Varible Frequency Drives ( 4 yesterday) for a variety of applications, mostly pumps. Ive never gone from 120 to 240 and Im not sure its possible to do so. Ive always gone from 220V single phase to 240V three phase. As a rule of thumb you will have to double the horsepower of the drive ( for a 3 hp motor you would need a 7.5 hp drive) and always make sure your incoming service is sufficient to handle the amp load. Most drive manufacturers have an online product selector to make sure you are getting the proper drive for the application.

Edited by LSnSC
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I install alot Varible Frequency Drives ( 4 yesterday) for a variety of applications, mostly pumps. Ive never gone from 120 to 240 and Im not sure its possible to do so. Ive always gone from 220V single phase to 240V three phase. As a rule of thumb you will have to double the horsepower of the drive ( for a 3 hp motor you would need a 7.5 hp drive) and always make sure your incoming service is sufficient to handle the amp load. Most drive manufacturers have an online product selector to make sure you are getting the proper drive for the application.

I have not wrapped my mind around that either...but the devices do exist.

Here is one of many examples

Edited by GunCat
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I've been using one of those

I install alot Varible Frequency Drives ( 4 yesterday) for a variety of applications, mostly pumps. Ive never gone from 120 to 240 and Im not sure its possible to do so. Ive always gone from 220V single phase to 240V three phase. As a rule of thumb you will have to double the horsepower of the drive ( for a 3 hp motor you would need a 7.5 hp drive) and always make sure your incoming service is sufficient to handle the amp load. Most drive manufacturers have an online product selector to make sure you are getting the proper drive for the application.

I have not wrapped my mind around that either...but the devices do exist.

Here is one of many examples

I've been using one like that since I installed my 2hp BP in my basement 8-10 yrs ago.

I did a TON of looking over on the hobbyist machining web sites and opted for one of these

vs. the cheap phase converters sold thru Enco and the like. (I think those breal more often)

I like the variable speed the VFD allows for me, my BP changes speeds with the belts so

no I pick a belt setting and adjust speed with the VFD.

I am not a machinist by any stretch, I make more bad parts than good but have a lot of fun doing it.

Good luck with your search.

ps, I brought a 220 line single phase to the VFD, just like a hot water line or well pump line.

Edited by 10mmdave
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If you can, run some 220 to your machine and buy a VFD rated for about 2hp. I have two TECOs (7300s with built in speed control by dial, IIRC) I bought from factorymation.com - they work great. For most uses I never have to swap speeds manually, but I still can if needed to get max torque.

If your motor will stand it (read the label and look for an inverter rating) you can run the speed up to about 1.5 whats on the label - so 90 hz instead of 60 which gives you1.5 the previous rpm. This is very nice if you need more spindle speed for small cutters or woodworking.

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I picked up a Delta VFD from the local motor shop that we've done business with for 40+ years. Opted for the 220 1PH in / 220 3PH out model rated 1-2 HP. Now to get another 220 circuit run and get this thing wired up.

I appreciate all the responses and advise in this thread, its been quite educational.

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