Is this hardware the right choice for my conversion to vfd-powered lathe?

Mikel Levy · Nov 22, 2017

I'm looking to replace the existing drive in my Colchester Chipmaster lathe (Kopp variator + 3hp/2.2kw single-phase motor) with a VFD and 2 or 3hp (1.5 or 2.2kw) 3-phase motor, running over a 20Hz-120HZ frequency range (nominal line frequency is 60Hz). I've tried to educate myself by reading various posts and tutorials, but I've only managed to absorb the basic concepts, so when it comes to choosing the right vfd for the job, I'm not convinced I'v selected the right piece of hardware. I also want to be sure a remote potentiometer may be wired in, instead of using the one next to the keypad. I am aware of the motor losing torque at lower frequencies and the pitfalls of using a non-inverter rated motor, etc. etc. The unit I've picked out (please see specifications in the image below--hope it's readable) seems like the best bang for the buck, but if anyone can suggest a better unit for the application, I'm all ears. This unit is selling for about $225 USD + shipping.

EDIT: Input to the vfd will be single-phase, not 3-phase, so correct model no. is L510-203-H1-U; all other specs are the same.

atomarc · Nov 22, 2017

Mikel,

I have a few thoughts as I've done more than a few of what you're contemplating.

Almost any modern drive will be able to be commanded for speed using a pot from any remote location, it's a standard logic feature of the drive.

Again, almost any motor will run forever with a drive regardless of being badged 'inverter duty'. You don't need to limit your motor choice to that style.

Many modern drives can be programmed to run in a vector mode which will allow very low speed with almost full rated horsepower.

A drive that is 'braking resistor' ready is a big plus. If your application might require stopping a heavy rotating load (chuck) quickly then stock DC injection braking alone may not be able to do it adequately.

When you shop for a drive, make sure it meets your HP requirements and that the drive does not need to be derated for single phase input..if that's whats available to you.

Everyone has their 'druthers' and I usually stick with Hitachi drives. Their model WJ200 is a reasonably priced, sensorless vector unit that has all the bells and whistles.

The TECO units are fine too. Whichever drive you decide on, try to find a vendor that will offer free technical support. Marshall Wolf Automation represents several brands and they have 'real people' you can get setup help from.

Stuart

naspc · Nov 22, 2017

Hi, I have been using a Lenze SMVector. The spec you list lots a lot like the one I have. I bought mine from precision-elecectric. They have a lot of information on these VFD. Craig makes YouTube videos as well. He is very knowledgeable on the subject.
I am a newbie but there is a lot of videos on these.

Buy ESV222N2YXB - 3 HP Lenze AC Tech SMVector Series VFD

rklopp · Nov 22, 2017

Mikel,
You indicated the current motor is single-phase, yet you chose a VFD needing three-phase input. Do you have three-phase supply? If so, then great, but if not, you need a VFD that accepts single-phase input, like the Teco on the line above the one you circled in the catalog.

Like Stuart, I think the Hitachi WJ200 drives are good. I have bought and use three by now, having tried Fuji, LG (built like a tank, but no longer available), no-name micro, several different Tecos, and Toshiba. The WJ200 has connections for a braking resistor, which is rather helpful for lathe applications, due to the long coast-down time otherwise. I am not sure the Teco you picked out has connections for a braking resistor, so you should verify. The cost may be low because that feature is not included.

I have a Chipmaster that I run on single phase power through an old LG Industrial drive. I rarely change the VFD speed, since the Kopp variator still works on my Chippie. The LG drive is a de-rated 5-hp unit that is built like a brick s***house.

RKlopp

Mikel Levy · Nov 22, 2017

rklopp said:
Mikel,
You indicated the current motor is single-phase, yet you chose a VFD needing three-phase input. Do you have three-phase supply? If so, then great, but if not, you need a VFD that accepts single-phase input, like the Teco on the line above the one you circled in the catalog.

RKlopp

My mistake, and thanks for pointing that out. Yes, I only have single phase input available. I simply grabbed the wrong spec lisitng from the TECO brochure.

--Mike

Jraef · Nov 22, 2017

Mikel Levy said:
... running over a 20Hz-120HZ frequency range (nominal line frequency is 60Hz). ...

So do you fully understand the consequences of this part of your plan? Once you run the motor at above 60Hz, it becomes Constant HP, so the torque begins to drop off. At 120Hz, your motor will have less than 1/2 of the torque that it offers at 60Hz (more of the current gets lost in inefficiencies as speed increases).

Principle-Operation-of-Variable-Frequency-Drive-VFD.jpg

Mikel Levy · Nov 22, 2017

Jraef said:
So do you fully understand the consequences of this part of your plan? Once you run the motor at above 60Hz, it becomes Constant HP, so the torque begins to drop off. At 120Hz, your motor will have less than 1/2 of the torque that it offers at 60Hz (more of the current gets lost in inefficiencies as speed increases).

I believe so, and because of the "loss" of torque (compared to a purely mehanical system) at frequencies below 60hz, I'll probably go with a 3hp motor, which otherwise would be overkill for tbe stuff I do.
--Mike

Mikel Levy · Nov 24, 2017

Thanks to all who responded. Fast braking is not an issue for me, so it looks like I'll go with the TECO unit.

--Mike

Monarchist · Nov 24, 2017

Mikel Levy said:
Thanks to all who responded. Fast braking is not an issue for me, so it looks like I'll go with the TECO unit.

--Mike

By now, you should qualify as an "informed consumer", can make a good choice.

Even so, braking needs or no, while the Teco is "adequate", I'd commit the rather modest difference (amortized over several years, after all) and step up to a Hitachi.. or better.

Closeouts & clearances on more "premium" brands such as AB, ABB, and such come by now and then as well. Check the major distributors, then vet the specific model with a Google search for "problems <make & model>" to see if it has a good track record. VFD designs, features, component selection, operating and power source limitations change OFTEN, and they change significantly, most major makers.

Some closeouts are last year's model, with several good years of field experience behind them - new model might simply be cheaper to build. Others are discontinued as problem children. A really NEW NEW one with very little exposure to real-world use may not turn out so hot as its lab tests thought it would. Design may be well-enough sorted, but the components generally go to the low bidders, etc.

Disclosure: The cheap VFD here is a Weg, the "better" one is a Schneider Altivar 71 series.

If I NEEDED another, I'd probably go for the KB "Hybrid", as programming steps are a nuisance (to me, anyway), and it has the same look, feel, neat NEMA 4X / IP65 case and general control placement as rather a lot of KB DC drives I use. NB: KB is not the ONLY maker to provide ruggedized enclosures.

IF/AS/WHEN ...one has to "remote" the entire VFD to the other side of a wall, ELSE spend a lot of time, money or SPACE for an enclosure to keep it clean, dry, cool, and safe?

THEN...it has become a "project" in its own right, rather than an "appliance", and not as much was saved as first appears.

2CW

B-Mathews · Nov 24, 2017

I will add that I have blown up two teco microdrives on my old Bridgeport. There IGBT's are undersized in my opinion. Go with the Hitachi for a few extra $. there much better components on their boards and handle what the teco would not without issue.Hatichal is also esier to program too.FYI Both the teco and Hitachi I used where rated for the same HP.(Apples to Apples) Also get the breaking resister. It will be very useful on a lathe if not for the safty factor alone. God forbid something happen and you need to e-stop the spindle.

Mikel Levy · Nov 25, 2017

Monarchist said:
By now, you should qualify as an "informed consumer", can make a good choice.

Even so, braking needs or no, while the Teco is "adequate", I'd commit the rather modest difference (amortized over several years, after all) and step up to a Hitachi.. or better.

Closeouts & clearances on more "premium" brands such as AB, ABB, and such come by now and then as well. Check the major distributors, then vet the specific model with a Google search for "problems <make & model>" to see if it has a good track record. VFD designs, features, component selection, operating and power source limitations change OFTEN, and they change significantly, most major makers.

Some closeouts are last year's model, with several good years of field experience behind them - new model might simply be cheaper to build. Others are discontinued as problem children. A really NEW NEW one with very little exposure to real-world use may not turn out so hot as its lab tests thought it would. Design may be well-enough sorted, but the components generally go to the low bidders, etc.

Disclosure: The cheap VFD here is a Weg, the "better" one is a Schneider Altivar 71 series.

If I NEEDED another, I'd probably go for the KB "Hybrid", as programming steps are a nuisance (to me, anyway), and it has the same look, feel, neat NEMA 4X / IP65 case and general control placement as rather a lot of KB DC drives I use. NB: KB is not the ONLY maker to provide ruggedized enclosures.

IF/AS/WHEN ...one has to "remote" the entire VFD to the other side of a wall, ELSE spend a lot of time, money or SPACE for an enclosure to keep it clean, dry, cool, and safe?

THEN...it has become a "project" in its own right, rather than an "appliance", and not as much was saved as first appears.

2CW

Thanks for the additional input. I'll look into the KB Hybrid.
--Mike

Mikel Levy · Nov 25, 2017

B-Mathews said:
I will add that I have blown up two teco microdrives on my old Bridgeport. There IGBT's are undersized in my opinion. Go with the Hitachi for a few extra $. there much better components on their boards and handle what the teco would not without issue.Hatichal is also esier to program too.FYI Both the teco and Hitachi I used where rated for the same HP.(Apples to Apples) Also get the breaking resister. It will be very useful on a lathe if not for the safty factor alone. God forbid something happen and you need to e-stop the spindle.

Good information, thanks.
--Mike

mksj · Nov 25, 2017

The Hitachi WJ200 is a fairly full featured mid range VFD. I have not seen and reliability issues with dozens of installs (short of incorrect wiring), Teco L510 is their newer low end line of Teco VFDs. Helped a few people with installing them, so far they have decent reviews and they are an entry level VFD. If replacing a motor, then I would recommend an inverter rated motor which are pretty much defacto, but their HP may not be maintained above about 1.5X their base speed. A 3Hp vector motor like the BlackMax or Baldor IDNM is usually rate at full Hp up to 6K top end. Still, I do not see a problem spinning a standard 1750RPM motor to 2X the base speed. You do loose torque above the base speed, but if you factor in the mechanical ratio needed for a fixed speed motor having to gear up to that speed, it is not a major issue. A bigger issue is loss of Hp below the base speed, so at 20Hz you will need to up size the motor. You will want a braking resistor with a lathe, it is not a simple install of just connecting the VFD direction inputs to the spindle switch and adding a speed pot, this represents a real safety issue. Also need to factor in safety interlocks and manual braking if the lathe has one. I have not had good results with KB VFDs with most machinery, very limited programming if any, and poor motor control/braking.

Mikel Levy · Nov 27, 2017

mksj said:
The Hitachi WJ200 is a fairly full featured mid range VFD. I have not seen and reliability issues with dozens of installs (short of incorrect wiring), Teco L510 is their newer low end line of Teco VFDs. Helped a few people with installing them, so far they have decent reviews and they are an entry level VFD. If replacing a motor, then I would recommend an inverter rated motor which are pretty much defacto, but their HP may not be maintained above about 1.5X their base speed. A 3Hp vector motor like the BlackMax or Baldor IDNM is usually rate at full Hp up to 6K top end. Still, I do not see a problem spinning a standard 1750RPM motor to 2X the base speed. You do loose torque above the base speed, but if you factor in the mechanical ratio needed for a fixed speed motor having to gear up to that speed, it is not a major issue. A bigger issue is loss of Hp below the base speed, so at 20Hz you will need to up size the motor. You will want a braking resistor with a lathe, it is not a simple install of just connecting the VFD direction inputs to the spindle switch and adding a speed pot, this represents a real safety issue. Also need to factor in safety interlocks and manual braking if the lathe has one. I have not had good results with KB VFDs with most machinery, very limited programming if any, and poor motor control/braking.

More good info--thanks.
--Mike

TorontoBuilder · Nov 26, 2022

Mike, what did you ultimately choose? The TECO L510 is capable of all the braking you'd need on your chipmaster.
I'm working on my own chipmaster conversion right now, having done my 12x37 lathe this year as well with a TECO VFD

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