Running a 3ph on 1ph Power- Which method?

[Bully]

I went and looked at a lathe today. It's a Harrison M300 in real nice shape. Price is right and I think the size would work well for my current and future needs. The motor is 3hp, 3ph.

I currently have 220 1ph in my garage which is where I plan to set this up. Can someone explain the major advantages/disadvantages between:
Static converter
Rotary converter
Variable frequency drive

I'm trying like heck to get all my ducks in a row to start gunsmithing on my own stuff but am not well versed in electricity.

Thank you in advance.

 

[Barrel Nut]

I have no idea what kind of motor mount your lathe has or what kind of drive connection, but my first try at solving this problem would be to replace the motor with a single phase one to match your existing power. Look here:
https://www.surpluscenter.com/Electric-Motors/
I've bought many motors, both electric and hydraulic (all brand new), from these guys over the years and every one of them has been perfect. Their prices are usually a fraction of the cost of the guys down at the local supply house.

 

[Cigarcop]

VFD for sure..... everything I have is 3ph running off a vfd with 220 going in to it.

I just bought a Mitsubishi VFD for my 3hp 3ph Clausing for $289
You can program it to do many things.

 

[Bully]

VFD for sure..... everything I have is 3ph running off a vfd with 220 going in to it.

I just bought a Mitsubishi VFD for my 3hp 3ph Clausing for $289
You can program it to do many things.

Mind if I ask what you can have it do?
Why did you not go rotary phase?

 

[TRA]

Forget the static. DO not replace motor! VFD is the simplest, but can often need tweaked by someone familiar with all the settings. Rotary has it's advantages, but is the most involved to set up. I ran CNC equipment for years on a rotary that I built.

I'd go with a VFD but get one big enough. Some can get pricey.

 

[dkhunt14]

Mind if I ask what you can have it do?
Why did you not go rotary phase?

I like the variable frequency drive. I have a vertical mill and the reversing switch went out. Couldn't get a switch because it was a 2 speed forward reverse. I went to a motor rebuilder. He said go with a variable frequency drive. He wired my motor on low leg so it would have power. He said now you will have more power and because of the variable drive it would run faster. I also now have variable speed which is nice. No noisy unit sitting around and it mounts right to the mill so you can see it. Now it is simple to reverse or speed up. Matt

 

[paperpuncher]

I run a rotary converter. Some pros and cons to consider. I have several machines in my shop and I can run them all from 1 converter. I thought the install was pretty simple. Downside it is an extra motor running and consuming power. I hate the noise from the motor running

 

[accuracyman]

Static phase converter-this device takes 220V single phase and temporarily generates a third leg upon startup then drops off once the motor spins up. Advantage is simple and inexpensive. Downside since you are running on two of the three legs you loose power.

Rotary phase converter- uses another motor to generate a third leg to add to the two legs of single phase 220v. This allows the motor to run at full capacity. Disadvantage is you have another motor running adding noise and usually the most expensive option because the motor must be larger than what you are trying to run.

VFD- uses electronics to generate the phases. Advantage is the motor is getting all three phases all the time so it runs at full capacity. A VFD varies above and below 60 cycle to control the speed of the motor. You can program the time it takes the motor to 'Ramp' up to speed and also the time to speed down. The variable speed and ability to control ramp up and down are nice advantages of the VFD. These can be had at very reasonable costs for smaller motors such as your 3 HP.

I hope I answered your question.

Kris

 

[Bully]

Static phase converter-this device takes 220V single phase and temporarily generates a third leg upon startup then drops off once the motor spins up. Advantage is simple and inexpensive. Downside since you are running on two of the three legs you loose power.

Rotary phase converter- uses another motor to generate a third leg to add to the two legs of single phase 220v. This allows the motor to run at full capacity. Disadvantage is you have another motor running adding noise and usually the most expensive option because the motor must be larger than what you are trying to run.

VFD- uses electronics to generate the phases. Advantage is the motor is getting all three phases all the time so it runs at full capacity. A VFD varies above and below 60 cycle to control the speed of the motor. You can program the time it takes the motor to 'Ramp' up to speed and also the time to speed down. The variable speed and ability to control ramp up and down are nice advantages of the VFD. These can be had at very reasonable costs for smaller motors such as your 3 HP.

I hope I answered your question.

Kris

Yessir. Thank you.

 

[sdean]

You will have to rewire every switch on the lathe through the VFD. Some electrical knowledge required.

 

[Alex Wheeler]

I have 3 machines and they all run off the same rotary converter. I have $150 into the converter. I thought it was very easy to set up. I would do it again if I started over. A vfd would be kind of nice to vary speeds, but so far I am happy.

 

[ebb]

Ive got a static that rune my mill, lathe, and radial arm saw (one at a time). If I were to do over I would go with a VFD they didn't exist when I set my stuff up.

 

[TRA]

You will have to rewire every switch on the lathe through the VFD. Some electrical knowledge required.

Why? The controls are usually if not always single phase. We use a bunch of VFD's every year and all they do is supply the unit with 3ph. Same as a rotary or static. The thing to remember with a rotary is if you have any "controls" on your machines, is to never connect the manufactured leg to the controls. They are usually powered off the #2 phase, or center lug at the machine. Personally I don't see the advantage of using a VFD to provide variable speed. You'd be better off setting the parameters to the motor and leaving them alone. We use them to fine tune a motor at a desired speed and load.

 

[akajun]

Why? The controls are usually if not always single phase. We use a bunch of VFD's every year and all they do is supply the unit with 3ph. Same as a rotary or static. The thing to remember with a rotary is if you have any "controls" on your machines, is to never connect the manufactured leg to the controls. They are usually powered off the #2 phase, or center lug at the machine. Personally I don't see the advantage of using a VFD to provide variable speed. You'd be better off setting the parameters to the motor and leaving them alone. We use them to fine tune a motor at a desired speed and load.

On a lathe, if your cutting a coarse thread to a shoulder, you can put the machine in low gear and really slow the speed down to avoid a mistake, also can fine tune your surface speed.
In my step pully mill, I leave it in high speed position and control my speed with the vfd and the back gear. Save a lot of time and again I can fine tune my speed

 

[TRA]

On a lathe, if your cutting a coarse thread to a shoulder, you can put the machine in low gear and really slow the speed down to avoid a mistake, also can fine tune your surface speed.
In my step pully mill, I leave it in high speed position and control my speed with the vfd and the back gear. Save a lot of time and again I can fine tune my speed

Quality threading requires a speed consistent with the material and your tooling. There's a limit to low speed threading.
Personally I'll take a step pulley Bridgeport any day over a VS machine. Although IMHO, VS lathes are the only way to go, but changing the frequency to slow down an electric motor has its negatives. Especially with induction motors.

As with everything there are pros and cons. Helps to know all the options. Especially when someone is looking for guidance.

 

[Bully]

I get that the static machines are simple and the biggest drawback from what I'm reading is that they have a hard start which can beat the motor up a bit.

The rotary machines are nice but burn a lot of power since they are constantly running. Plus the noise gets annoying.

The VFD seem to be a good compromise however I just can't wrap my head around needing variable speed when the lathe has gears to vary the speed. Seems redundant.

Additionally I'm a bit confused: Does the machine ONLY turn on at the VFD or do you power the VFD and then turn the machine on when the operator is ready to turn it on and for safety, does it turn on at the VFD or on the machine?

 

[sdean]

Why? The controls are usually if not always single phase. We use a bunch of VFD's every year and all they do is supply the unit with 3ph. Same as a rotary or static. The thing to remember with a rotary is if you have any "controls" on your machines, is to never connect the manufactured leg to the controls. They are usually powered off the #2 phase, or center lug at the machine. Personally I don't see the advantage of using a VFD to provide variable speed. You'd be better off setting the parameters to the motor and leaving them alone. We use them to fine tune a motor at a desired speed and load.

You are not supposed to have any switches between the motor and the VFD. You could use the VFD panel to control everything but to use the switches on the lathe they would need to be rewired through the VFD. On my two VFD's it says the VFD should be wired directly to the motor.

 

[TRA]

You are not supposed to have any switches between the motor and the VFD. You could use the VFD panel to control everything but to use the switches on the lathe they would need to be rewired through the VFD. On my two VFD's it says the VFD should be wired directly to the motor.

You're right, the way I worded that was confusing. The vfd would go between the controls / switches, but they are already separate from the load. They are, on anything with the exception of very small hp motors as the switching loads necessary are over most all switch ratings.

I'm in a environment where all motors have to be safety connected to a drive. IE, all drives must be connected to the motor via safety rated contactors. The contactor is then energized by a switch. It's law, code. The problem is very few drives can tolerate the inrush current from disconnecting while under power. Safety rated VFD's are pricey.

Hooking up a low power machines like a small mill or a table saw is quite different from anything that uses contactors or motor starters to drive the motor.

I get that the static machines are simple and the biggest drawback from what I'm reading is that they have a hard start which can beat the motor up a bit.

The rotary machines are nice but burn a lot of power since they are constantly running. Plus the noise gets annoying.

The VFD seem to be a good compromise however I just can't wrap my head around needing variable speed when the lathe has gears to vary the speed. Seems redundant.

Additionally I'm a bit confused: Does the machine ONLY turn on at the VFD or do you power the VFD and then turn the machine on when the operator is ready to turn it on and for safety, does it turn on at the VFD or on the machine?

From reading the responses of these inquires, there are guys here doing it both ways.

These discussions have the potential to be right or wrong, due to the application. It pays to have a qualified electrician give them an on site evaluation. At least a detailed description (photos) of your equipment. With a rotary you don't have all these issues.

I have never seen any large electrical usages due to a rotary converter. There is no load on the converter other than what the driven unit would draw. My large converter did not draw much load at all. It's basically idling at speed 99% of the time. They are noisy, that is a given. Rotary converters have been a lifesaver for farmers since the first power lines were run. Where I live all 3ph used to be considered commercial and very expensive.

 

[Bamban]

What can you do with a VFD.

Here is a picture of my 1024 with VFD, my 1236 has a VFD as well. The 1024 has a proximity sensor, that shuts the spindle when tripped. Convenient when threading to a thread relief like on the AR barrels.

The control box on the top L has the toggle, speed, braking switch to select the shutdown, whether coast along or right now, , and eStop The control box under the pan contains the forward, reverse, stop, and bypass for the proximity sensor.

Here is a short video on how the threading with the proximity sensor works. I have run it at 400 RPMs to the thread relief during testing, and it works.

 

[Rich S]

I'm running a rotary to power a 5 hp lathe and 3 hp mill. No issues other than the extra noise as others have mentioned. If going with a rotary you can get by fairly cheap by buying the control pannel then buying a used motor for the idler. Small used 3 phase motors can be found fairly cheap. A general rule of thumb is you want your motor/idler to be twice the size of you biggest driven load. If it will be mounted near your equipment find a TEFC rated motor. Mine is close to the mill and I've had no issues with the total enclosed motor. I originally planned to use a VFD but the options get limited for 5 hp and up. For a 3 hp motor VFDs are as cost affective as a rotary. The VFDs provide some additional options also. A more true phase angle than the rotary, variable speed and no additional noise are probably tops. You could also set up soft starts, dynamic braking, ect.... If you go the rotary direction, I can provide where I bought the control pannel. An individual sells them on Ebay at a reasonable cost, provides good directions and phone support.