Trouble Picking a VFD for South Bend 13 Lathe

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GForceJunky

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Like the title says, I'm having trouble deciding on a VFD for my new (to me) South Bend 13" x 5' lathe.

Motor specs as follows:
  • Frame: 182
  • Phase: 3
  • HP: 1
  • Voltage: 208-220/440
  • Amps: 3.6-3.4/1.7
  • RPM: 1730
  • Service Factor: 1.25
It's a Westinghouse Life-Line A motor.

I will happily buy a used VFD if the price is right, but just as happy to buy new for the peace of mind. Budget is a key factor but not to the point it significantly limits capability. Not looking to spend a fortune but it definitely needs to have braking capability and any other features one might want/expect/need for use with a lathe. I can supply the VFD 110 or 220V single phase power (I have outlets for both).

I have looked at various retailers selling VFDs as well as places like eBay and the more I look the less sure I am. Choice overload!

Some that I have seen and considered (mix of new and used) are the following models:

Eaton DC1-127D0NN-A20CE1
Eaton Cutler-Hammer MVX002A0-2 MVX9000
MITSUBISHI, FR-S520-1.5K-NA
Fuji Electric FRENIC-Mini C2 230V 3HP Variable Frequency Drive (FRN0012C2S-7U)
Teco/Westinghouse L510-202-H1-U

If it matters or if anyone has specific leads, I am located in SE Michigan (Detroit area).

I would also consider replacing the motor altogether but odds are any single phase 182-framed motor will be more than a good VFD and won't give me the capabilities I want (braking, etc.) anyway.

Thanks in advance for any insight/advice!
 
I've had good luck with the generic Chinese VFD's although I did buy a nice TECO for my first conversion on my Seneca Falls. If braking is a concern then you may want to go with something nicer.

This is the one I just bought for my belt grinder.


Automation Direct has a good selection and customer service but for me this just isn't worth spending too much thought on unless you're building a sophisticated control like @mksj does.

If you just need it to power the lathe and have variable speed the cheaper the better in my opinion....

John
 
matthewsx said:
I've had good luck with the generic Chinese VFD's although I did buy a nice TECO for my first conversion on my Seneca Falls. If braking is a concern then you may want to go with something nicer.

This is the one I just bought for my belt grinder.


Automation Direct has a good selection and customer service but for me this just isn't worth spending too much thought on unless you're building a sophisticated control like @mksj does.

If you just need it to power the lathe and have variable speed the cheaper the better in my opinion....

John
Click to expand...

Hey John,

Thanks for the input! My main requirements are:

- Good quality/reliable (and ideally NOT made in China)
- Variable Speed
- Braking
- Ease of use/setup

I'll have to dig through posts to see mksj's work but for now I just want it running. Eventually I may want to really dig into some of the advanced features but low priority. I really actively try to avoid anything made in China though so unless it's going to cost me WAYYYY more to get USA/Japan/Europe/etc. that's a pretty firm one.
 
Here's one made in Brasil


I don't know what your technical requirements are so no idea if it will meet them but it is only ~4 times what the Amazon unit I posted is.

If you want to prepare for future features I'd definitely recommending reading some of Marks posts ore reaching out to him direct.

You can also go with used from eBay but that has it's risks too....

John
 
I would not recommend buying used off of eBay/non-authorized sellers, if you have any issue or need technical support it won't be there. I also do not recommend buying them off of Amazon, or directly from China for the same reasons, unless budget is an over riding factor. NOS or used VFDs, it just doesn't pay for a number of different reasons. Many of the VFD's sold on eBay may have sat on the shelf for years, and the capacitors are at higher risk of failing on power up, also some VFD are special purpose and cannot be programmed. You do not need to oversize a VFD if you are not planning on going to a larger motor at some later point, but if the price difference is small say for a 1.5 Hp vs. 1.0, then I would up-size, the key point is looking at the VFD output amps and that they are greater than the motor amps after factoring all the de-ratings.

You also need to be careful of the specifications, so the Teco L510 does not support an external braking resistor, nor does WEG CFW300/500 series in the 2Hp and under sizes. Many of the cheaper Chinese VFDs do not have the braking chopper even though the braking wire terminals are there. Automation Direct has the GS21 series VFD's which are decent, but they have been out of stick for months. Eaton, I haven't worked with, if buying new they are a bit pricey. The Fuji Frenc Mini is a reasonable option, also the Hitachi WJ200 is probably the most frequently used VFD in this forum. These will al run in the $220-250 range. Teco has a higher level VFD the E510 series which is more expensive. Invertek VFD's are fairly basic/easy to install, but I find there number of inputs and limited programming to be very limiting when used for lathes. If you do not plan on oversizing the motor then I would recommend the Hiatchi WJ200-007SF and you will find a number of posts on programming parameters in this forum. I mostly work/use 4-5 brands of VFD's so I do not need to decipher the manual and programming parameters for the others.
www.wolfautomation.com

VFD, 1hp, 5.5A, 230VAC, Single Phase Input, Compac

VFD, 1hp, 5.5A, 230VAC, Single Phase Input, Compact Micro Drive, Easy To Use, Optional NEMA 1 Kit: NEMA1-C2-104 and Optional DIN Rail Mounting Adapter: RMA-C1-0.75 Available to Order Separately
www.wolfautomation.com www.wolfautomation.com
www.wolfautomation.com

VFD, 2hp, 9.2A, 230VAC, Single Phase Input, Compac

VFD, 2hp, 9.2A, 230VAC, Single Phase Input, Compact Micro Drive, Easy To Use, Optional NEMA 1 Kit: NEMA1-C2-204 and DIN Rail Mounting Adapter: RMA-C1-2.2 Available to Order Separately
www.wolfautomation.com www.wolfautomation.com
www.driveswarehouse.com

WJ200-007SF

www.driveswarehouse.com www.driveswarehouse.com
 
I will second the Hitachi units. They are SO MUCH EASIER to program and read the manual. I've cheaped out a couple times and been sorry.

This is very important for those of us that only do a VFD on rare occasion.
 
John, Karl, and especially Mark, thank you for the wonderful insight!

Mark, everything you've written is super helpful and really clarifies a lot for me - particularly regarding the braking aspect. The 2hp Frenic is only a few dollars more than the 1hp Hitachi. The 1.5hp Hitachi is a 20-25% more than either of them. It seems like the 2hp Frenic is the best bang for the buck of the listed option. Is there any good reason why

I don't plan to upsize/upgrade the motor unless the current one dies out. That being said, one thing I didn't factor in is that I do plan to get a mill (though likely at least 8-12 months out) which makes me wonder if 2 VFDs or 1 RPC is better. I do like how compact the VFDs are, especially for my tiny shop, and the added capabilities they provide is nice! I don't have any intentions of adding additional 3Ph machinery to my little garage shop beyond those two as there's just no room, so I'm quite certain 2 large machines is a hard stop. I am highly inclined to just get another VFD when needed vs 'future-proofing' with a large RPC.
 
Motors this small really do not need braking resistor.

The better VFD has a programmable ramp up and ramp down.

By using the ramp down feature, the VFD powers the motor at slowing speed until it stops.

The motor brakes itself.

Sent from my SM-G781V using Tapatalk
 
I have not directly installed any of the Fuji VFD's but they are often recommended by Wolf Automation and for the most part they have good technical support. I can also provide some direction if you need it. If the Automation Direct VFD was available, I would recommend their GS21, primarily because I find their manuals to be a bit more user friendly. But they all are similar as to how they operate and programming, I have had more issues with some of the generic (Amazon) VFD's primarily because the manuals are so poor and the programming can be challenging/lack of parameters. That is just my experience. If just 2 machines and both are 3Hp or less I would recommend two VFD's, if more machines and a larger space maybe an RPC, or consider a Phase Perfect which electronically gives you fixed regulated 60 Hz 3 phase from single phase input power. They are priced competitively with store bought RPC's, and electrically they are much more efficient. The use of fixed frequency generators for 3 phase vs. VFD depends on each situation. The latter is pretty much plug and play, a VFD will require rewiring and programming which can be a bit more intimidating. There are also safety issues with how you install the VFD as previously mentioned, and each VFD model is different on how it works and is programmed. Like any piece of machinery there is a learning curve to its proper use.

As far as VFD braking, I will diverge a bit from the recommendation that you do not need a braking resistor, it comes down to how fast you want a machine to stop. VFD's do have an internal braking resistor and a circuit to modulate its cycling based on the programmed stopping parameters. If it is just a motor stopping, a VFD can stop a smaller motor in 1-2 seconds, add some mass and speed to that and you are in the 3-5 seconds range (and longer for high momentum systems). You also risk a buss over voltage error in where the regeneration energy raises the VFD buss voltage to a point where it disconnects from the output to prevent damage and this puts you into a free run mode with no braking. So in a lathe this can be a bit more dangerous if you expect the chuck/feed to stop fast and it doesn't. I had issues with this occurring with all sizes of motors in different applications, so if you want fast stopping (like an E-Stop) then adding an external braking resistor is recommended and is a nominal cost. There is also DC injection which works at low Hz to stop/lock the motor which is different then a braking resistor. On the lathes where I need braking in1-2 seconds, and with an electronic stopping system it is important that there is a high degree of repeatability, this requires the addition of an external braking resistor along with adjustments to the VFD parameters. On a mill this is less of an issue, but if you want a fast E-Stop and/or for reverse tapping then one needs to factor in an external braking resistor.
 
Mark,

Thanks again for the super informative and detailed reply. It really does help lift the fog.

Even with the added work of getting a VFD set up properly/well, I think it makes sense to stick with my original plan of getting another VFD when I eventually get a mill - an idea you agree was likely best for my hypothetical situation.

With regards to braking, I absolutely want something that will slow down very fast and I would definitely like to add an e-stop, whether it's a 'knee paddle' style or a foot brake style (connected to an electrical switch, not an actual mechanical brake), I would like something. I will almost always be working alone - it's important to me to be as safe as possible. To accomplish this with any of the recommended VFDs, am I correct in my understanding that it is highly desirable (if not outright required) to add an external braking transistor?

For a mill, I'm sure any VFDs fast ramp down would be adequate. I know I've read about people using braking along with other features for things like tapping and whatnot but for a mill I'm not too concerned.

I will likely reach out a little further down the road once I actually buy a VFD, finish my lathe rebuild, and go to wire it all up and get the settings sorted.

Now to decide which of the VFDs to buy and just do it.
 
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