# VFD as a basic phase converter



## Tolerent (Apr 12, 2020)

Looking to power a 3 phase 2 HP lathe with a 3 HP VFD. Selected the 3 vs 2 HP VFD to lower the load stress on the VFD. Planning to run the VFD off a disconnect from the main panel and disconnect it 90% of the time e.g. when the lathe is not in use or going to be used within a few hours. Not planning to shut the VFD off if I take a run to grab lunch or the store. Output of the VFD direct or through a disconnect or plug to line wiring for the Lathe. Not planning to use the VFD for speed control, soft starts etc. Just power to the lathe. 

Is this a reasonable approach?

What wear and tear on and electrical usage from the VFD if I simply leave the VFD on all the time (anticipating the lathe runs a few hours weekly)?

What abuse to the VFD with me cycling and interrupting the load while the VFD is in a constant supply mode?

How involved to make use of the frequency control and soft start features of the VFD?

PM1340 3PH to https://www.automationdirect.com/ad...equency_drives_(vfd)/general_purpose/gs3-23p0


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## Ulma Doctor (Apr 12, 2020)

yes, this is a reasonable approach.
i have taken the very same approach and the the results have been good for 4 years of testing
i have not had a single failure on more than 20 machines equipped with cheap chinese VFD's

the fans will cycle on and off periodically.
there is not a lot of overhead current flow in the ready state, so not a tremendous amount of heat is generated.

let me be clear- you don't want to disconnect the power to the VFD while taking cuts- that's bad
if you wish to simply shut off the VFD from a ready state without taking cuts, there is no danger there.
i use Twist lock plugs on my VFD's at home and in the field. i disconnect power at the plug when i'm done with a machine.
i also have heavy duty power interlock devises that are effectively heavy duty light switches,
to disconnect power between the incoming power plug and the VFD on many devises. this is another approach you may emulate too

soft starting is very simple, most vfd's make that very easy by changing a few parameters in the set up

in the link,
that's a nice drive, but i have spent less than $100 on a VFD and got a lot of bang for my dollar.
i have a small 1.5hp single to 3 phase VFD that was less than $50 that just won't break-
i have done almost everything i can think of , including placing VFD control into the hands of Butchers-
somehow the drive survives, don't ask me how.


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## ttabbal (Apr 12, 2020)

Most VFDs don't like to have the motor connections messed with while running. They need feedback from the motor to control the phases. Many of the cheaper units will fry if you disconnect the motor while it's running. These are not like static or rotary phase converters. The common instructions I have seen are to wire the motor directly to the VFD outputs. No switches or other controls in the path. 

You don't have to allow for speed control etc.. But the VFD has to control the motor and power on/off is via the VFD.


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## Tolerent (Apr 12, 2020)

ttabbal said:


> Most VFDs don't like to have the motor connections messed with while running. They need feedback from the motor to control the phases. Many of the cheaper units will fry if you disconnect the motor while it's running. These are not like static or rotary phase converters. The common instructions I have seen are to wire the motor directly to the VFD outputs. No switches or other controls in the path.
> 
> You don't have to allow for speed control etc.. But the VFD has to control the motor and power on/off is via the VFD.



So, are you saying I should *not *use the VFD to supply an outlet that powers a Lathe and then use the Lathe's native control system to control the lathe?


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## Tolerent (Apr 12, 2020)

Ulma Doctor said:


> yes, this is a reasonable approach.
> i have taken the very same approach and the the results have been good for 4 years of testing
> i have not had a single failure on more than 20 machines equipped with cheap chinese VFD's
> 
> ...


Quick shopping found this for $207: https://www.vfds.com/variable-frequency-drives/3hp-220v-galt-electric-g200-vfd-g22s000100ul01

Link to your preferred VFD venue?


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## JimDawson (Apr 12, 2020)

I have that same drive on my mill, I have shut it off twice in about 3 years (other than the occasional power fail, like every time the wind blows over about 30 knots) The VFD is hard wired to my breaker panel, and the motor is hard wired directly to the VFD.  All of the control is done at the VFD control inputs.

Under no condition do you want to disconnect the motor from the VFD when powered on.  The VFD can not be used as what you might call a phase converter to supply 3 phase line power in the normal sense.

The Start/Stop, For/Rev circuits are pretty simple, and the documentation on that is very good.  You will want to wire around your existing lathe controls, and use the existing lathe switches to control the VFD.


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## Ulma Doctor (Apr 12, 2020)

i have bought 4 of these









						3HP 1.5KW Single Phase To 3/Three Phase Output Frequency Converter VFD 220V  | eBay
					

Find many great new & used options and get the best deals for 3HP 1.5KW Single Phase To 3/Three Phase Output Frequency Converter VFD 220V at the best online prices at eBay! Free shipping for many products!



					www.ebay.com


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## mksj (Apr 12, 2020)

You buy an expensive lathe, I would not put on an inexpensive VFD. You do not need to oversize the VFD, if it is running at its rated output. A VFD should be left on as long as you need to work with it, frequent on/off cycling will lead to a faster degradation of the components, so I recommend turning off at the end of the day more for safety reasons.  You also cannot use the VFD as a plug and play 3 phase generator, it needs to be directly wired to the motor and you need to use the VFD low voltage control inputs and retain the safety features of the lathe. This has been outlined on how to do this in previous posts.








						Pm1340gt Lathe Basic Vfd Control Conversion Using The Stock Control Board And Switches
					

Many individuals buy the PM1340GT lathe as a 3 phase machine with the intent to convert it over to a VFD system, the usual VFD that is used is the Hitachi WJ200-015SF. Unfortunately the conversion often requires a somewhat complex and costly conversion process to optimize many of the VFD...




					www.hobby-machinist.com


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## matthewsx (Apr 12, 2020)

I have a nice TECO and also the same unit as Ulma Doctor, they both provide 3 phase and will do the same job. The TECO has better instructions but I can program the cheap one with a little figuring which is necessary in either case.

Jim is right, you do not want to use a VFD to power your machine from the plug. It does take a little more work to wire it directly to the motor and control circuits but once it's done you're golden. Infinite variable speed within the range your lathe runs is really nice to have and I wouldn't be without VFD control on any serious lathe. Quite a few folks on here have done it and can probably help you out, with your background it should be fairly easy and you will know your machine better when done.

If you don't want to mess with that just get a static phase converter and hook it up like normal with the stock input. It will work fine and you won't have to modify anything.

Sounds like you've made a good choice on the lathe 

John


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## ttabbal (Apr 12, 2020)

Tolerent said:


> So, are you saying I should *not *use the VFD to supply an outlet that powers a Lathe and then use the Lathe's native control system to control the lathe?



Correct. I've read that will kill VFDs. I've never tried it. If you want that sort of setup you need a static or rotary converter. You can also wire the controls to the VFD, though that gets more complicated. I built a simple control box to replace the rotary switch on the Bridgeport for that reason. 

I have some plugged in all the time, and some that get disconnected. No trouble yet, but in theory the inrush surge when first powered can wear components faster.


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## Tolerent (Apr 12, 2020)

So, I would need to get this VFD for $420: https://www.galco.com/buy/Hitachi/WJ200-022LF
AND the appropriate braking resistor for about $20
AND then follow the instructions in the MKSJ PDF and a few hours later I will either have:

A sweet running lathe.
or a migraine headache and a very expensive jigsaw puzzle.
Who has followed the PDF with a different Make and Model VFD and what was the process and outcome?


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## matthewsx (Apr 12, 2020)

Tolerent said:


> So, I would need to get this VFD for $420: https://www.galco.com/buy/Hitachi/WJ200-022LF
> AND the appropriate braking resistor for about $20
> AND then follow the instructions in the MKSJ PDF and a few hours later I will either have:
> 
> ...



That's a nice VFD but not for your use since it requires a 3 phase input, you should be able to get something just as good for a little less than that. As for being able to do the conversion, it's been done lots of times by folks no smarter than you, but if you don't want to mess with it then get something like this:



			https://www.grainger.com/product/PHASE-A-MATIC-1-3-HP-Phase-Converter-2MV47
		


And wire it between your 240v single phase supply and your new lathe.

Done.

John


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## Tolerent (Apr 12, 2020)

This $361 VFD... https://www.galco.com/buy/Hitachi/WJ200-015SF
Or $300 if still available: https://www.ebay.com/itm/HITACHI-WJ...591496&hash=item2157d4d6d1:g:PM4AAOSwdQda6w6V

As direct literal parts for the PDF instruction then?


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## matthewsx (Apr 12, 2020)

The eBay listing says more than 10 available so you should be fine there. 

As long as you get single phase input (240v, 60Hz) and 220v three phase output at 9 amps or better any VFD should work. The differences are in control circuits, programming, documentation and support. For the money you're spending on the lathe, saving ~$200 on a VFD probably isn't something to worry about and using the same parts as  Mark should make it less stressful. 

You're going down a well traveled path here and there are many guides available along the way 


John


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## Tolerent (Apr 12, 2020)

"Going down a well traveled"...  

When I was in High School someone told me everyone was doing... Oops. Never mind.


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## cathead (Apr 12, 2020)

A double pole single throw relay works well on an incoming 220 line.  The relay is simply operated with a
single pole toggle switch that applies 120 volts AC to the relay.  The control circuit can be light duty wire
and most any on-off switch will be fine.  You don't have to unplug anything or dump a breaker, just
turn it on or off.  The relay I used is a DPST rated at 20 amperes and runs on 120 volts AC.


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## Ulma Doctor (Apr 12, 2020)

i have worked with very expensive and very cheap drives. the only real difference is how much money you want to spend.
expensive drives don't have magic inside of them, they can fail too.
i'd rather spend the extra money on tooling or other tools


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## Tolerent (Apr 12, 2020)

Ulma Doctor said:


> i have worked with very expensive and very cheap drives. the only real difference is how much money you want to spend.
> expensive drives don't have magic inside of them, they can fail too.
> i'd rather spend the extra money on tooling or other tools


Programming is likely going to require the same amount of drilling into reference material? 
My biggest concern with a cheap drive is technical support in the form of readable and understandable reference materials.


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## mksj (Apr 12, 2020)

VFD is the WJ200-015SF which is $275. https://www.driveswarehouse.com/wj200-015sf
Many of the less expensive VFD's lack both the programming parameters needed for a lathe and the braking circuitry/parameters. QED.
The programming is simple, because it is all laid out for you, no futzing and trying to figure out why it isn't working. Look at the number of threads on people posting how do I program XYZ VFD and find out it either doesn't work or the manual is so poorly written even technicians can't figure it out. You look at the DOA rate of say the HY VFD's and they are reported to be as high as 25%, and from people that work on these for a living, there is a big difference between the generic Chinese ones and more name brand.  In the past 10 years I have yet to see a VFD failure with a Hitachi, Yaskawa or Teco drive, dealing with numerous people. 

The few HY/generic VFDs installs I have worked with individuals on have been a nightmare. Bottom line if they work and do not fail up front they are likely to work for a while longer, their programming and interfaces is poor and you typically get no support or warranty. Is it worth $100 difference on a $5000 lathe.


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## Tolerent (Apr 12, 2020)

mksj said:


> VFD is the WJ200-015SF which is $275. https://www.driveswarehouse.com/wj200-015sf
> Many of the less expensive VFD's lack both the programming parameters needed for a lathe and the braking circuitry/parameters. QED.
> The programming is simple, because it is all laid out for you, no futzing and trying to figure out why it isn't working. Look at the number of threads on people posting how do I program XYZ VFD and find out it either doesn't work or the manual is so poorly written even technicians can't figure it out. You look at the DOA rate of say the HY VFD's and they are reported to be as high as 25%, and from people that work on these for a living, there is a big difference between the generic Chinese ones and more name brand.  In the past 10 years I have yet to see a VFD failure with a Hitachi, Yaskawa or Teco drive, dealing with numerous people.
> 
> The few HY/generic VFDs installs I have worked with individuals on have been a nightmare. Bottom line if they work and do not fail up front they are likely to work for a while longer, their programming and interfaces is poor and you typically get no support or warranty. Is it worth $100 difference on a $5000 lathe.


I agree. Thanks everyone for the valuable insights and advice. You are a treasure.


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## f350ca (Apr 12, 2020)

I have the 2 HP version of the Automation direct one on a radial arm drill. Works well, the manual is in english, even I could follow it and their technical support is great. My drill uses a two speed motor, questioned them about leaving the switch in to change speeds, they said no problem as long as the output is off, no need to kill the input power. This is as I thought but nice to talk to someone who actually knows and isn't just giving an opinion
Having said that, my opinion, lol, if you have a gear head lathe I wouldn't recommend using motor braking. Soft start is great to reduce the instant load on the gear train, motor braking is instantly removing the lash in the gears. On belt drive machines its great.

Greg


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## Hawkeye (Apr 12, 2020)

I use a Teco to power both my mill/drill and my big lathe. I built a housing for the VFD and an array of relays to switch between the two, plus the input for the tachometer. The selector switch can't change between machines if there is any output flowing (another relay). I really like the precise speed control it gives me, especially on the mill. I might change belts once a year or less. The lathe has a 3-speed gearbox for when I need a different range. Lots of speed control within each range.


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## AGCB97 (Apr 13, 2020)

Programming of a VFD is not a steep learning curve, only a new experience if you've never done it. There are so many useful features available by doing a little "one time setup' that the small time spent has great rewards.

I have 2 VFDs, one $60 unit powering the Powermatic drill press and the other sharing duties for the Bridgeport and Gardner surface grinder. They are never used at the same time so I simply plug the machine to be used into an outlet at the VFD (power off at the main panel). Both motors are 1-1/2 HP and similar so no need to change the VFD in any way. There is a small home made panel near the Bridgeport with pot for frequency control, forward/reverse switch and machine power on/off switch. Easy peasy to wire.

As far as I'm concerned, paying a bunch of money for perceived reliability or insurance or support is a waste.
These things are so commonplace today that apart from self (i.e. yourself) inflicted damage they are completely reliable as advertised (power wise). In other words, no need to size up as parameters are programmed in for protection.

MHO
Aaron


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## 7milesup (Apr 13, 2020)

Surprised no one mentioned Huanyang VFDs.   I have this one from Amazon on my Bridgeport surface grinder. Works fine. Only caveat is that one in my link does not have an option for a braking resistor. I did not think that would be a big deal but now wish it had it since it takes a while for my grinding wheel to come to a stop.


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## markba633csi (Apr 13, 2020)

HY VFDs were mentioned in post #19-  many people  have had good luck with them but I have heard of some fails too
personally I would buy one of the name brands- I have experience repairing electronics but I would not want to troubleshoot a cheap VFD, especially without a schematic
-Mark


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## JimDawson (Apr 13, 2020)

I will pay a bit extra for good tech support and readable, well laid out documentation.  That along with free 2 day shipping makes Automation Direct units pretty attractive.  HY VFDs are OK, if you get a genuine HY.  There are knock-offs of the HY line.  There is some issues with the SVC functionality with the HY units. I do have a HY 10HP unit running my air compressor.

I have AD GS3 units on both my mill (3 HP) and CNC lathe (10 HP).  I also have a couple of the GS2 units on other equipment.


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## ErichKeane (Apr 13, 2020)

I've got a couple of the HY VFDs that I'm quite happy with.  They work great once you get them setup, and I'm pretty good at reading the crappy quality manuals.  

While a higher quality one might be nice, I figure these are disposable, and I won't really mind if they break.  My shop is wood + metal, so its a pretty harsh environment.  Interestingly, the only failure I've had so far is a Hitachi (vs 4 HY), which is the one I babied/protected the most!


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## JimDawson (Apr 13, 2020)

ErichKeane said:


> Interestingly, the only failure I've had so far is a Hitachi (vs 4 HY), which is the one I babied/protected the most!



I also have a Hitachi that blew up.


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## Tolerent (Apr 13, 2020)

So, the wiring pinouts are going to be identical or easy to translate and the setup and footprint are the primary differences? I would not want to troubleshoot a cheap drive that blew up, but even at $300 for a Hitachi I think I would most likely simply replace a drive after the smoke escaped.


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## mksj (Apr 13, 2020)

Probably worth reading some of the reviews" https://www.amazon.com/HY-HUANYANG-Variable-Frequency-Converter/dp/B07HDYX25C?th=1
3.0 out of 5 stars 25% Failure Rate out of the Box
Reviewed in the United States on December 1, 2018
Size: 220V power inputColor: 2.2KWVerified Purchase
I've used about 100 of these VFDs over 5 years. About 20% - 25% don't work right out of the box. HOWEVER, those that do work, do work pretty well and only 1 failure of the 100 or so after being put into service. SO they do work but its frustrating to get a dud right out out of the box.

2.0 out of 5 stars Works
Reviewed in the United States on June 23, 2018
Size: 220V power inputColor: 2.2KWVerified Purchase
I have 3 of these that work well, Actually, I now have 4 of these. I bought 2 six months ago for a G0602 cnc lathe project. One of these recently failed while I was programming it before i event attempted to power the motor. Dead Short across terminals 1 & 3. Tripped 3 breakers including a 50 amp sub panel. So the 25% failure rate is still accurate. . If anyone from Amazon or Huanyang actually reads these, contact me if I have any recourse for compensation 

As I indicated, everyone has a different experience of what worked and didn't work, but typically the N (units studies) is very small. All VFD's will fail at some point, and the technology is continuously changing and they are built to different price points and features. There is also a big difference as the application and duty cycle, it it is used occasionally or 24/7. So one chooses accordingly and to the price point you want. Most of these are disposable if something goes, until you get into the larger more expensive units which are designed to be rebuildable. The most common mode of failure these days are the capacitors, in particular if the unit has been sitting on the shelf for a long period of time. My N so far is probably in the 100's, but all of this is relative because I do not do industrial work. I do participate in other forums, so some of my comments are based on what others have documented.

Where I tend to disagree with some of the comments above is the understanding an ease of programming. My first couple of VFD systems took me months to design and fine tune the programming parameters, and even on some recent Yaskawa VFD systems I am still fine tuning parameters months after the install. These parameters significantly differ between the type of machine and the motor characteristics. So there is a learning curve and most people can get it to work, the question is how much time do you want to spend figuring it out and is it safe. Do you understand that hitting the E-Stop may or may not quickly stop the machine based on the program parameters you used. I had this with my lathe the other day.

If you want to put some marginal VFD on a mill, no problem. Work on some machines that have more momentum or interlock safety features, and have a smaller safety margin, well do it at your own risk. I have no issues with going cheap, but I can't tell you the number of people I have had to help with these types of VFDs, and for newbies it is not as straight forward and often just getting the wiring correct is a major hurdle. Nothing against learning, but helps when you have a starting point and one reason why we share our experiences. Nothing is absolute, just shades of grey.


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## ErichKeane (Apr 13, 2020)

Tolerent said:


> So, the wiring pinouts are going to be identical or easy to translate and the setup and footprint are the primary differences? I would not want to troubleshoot a cheap drive that blew up, but even at $300 for a Hitachi I think I would most likely simply replace a drive after the smoke escaped.



The HYs are all similar enough that I've had no problem wiring/programming them.  The 10HP I bought was a little more difficult since it had more options, but it was easy enough.

When the HY is ~$100 vs the Hitachi being ~$300, I just needed good enough.  

That said, I'm a home shop hobbiest. If it blows up, I go do something else and wait for a replacement. The $200 difference being spent on tools or materials is more beneficial to my hobby than a more reliable or easier to program VFD. When it comes to my big VFD, I saved more than $500 vs a comparable Hitachi, which seemed particularly worth it to me.


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## Twirpunky (Apr 13, 2020)

If all you want is simple single to three phase, why not use a rotary phase converter?  I bought a panel from phase-craft (no longer in business) for around $200 and used a 5 hp 3 phase motor I had laying around.  Cheap, easy, and durable as heck.  Several companies sell panels.  I wish phase-craft still sold panels.  They were very well constructed and worked great.  Lots of guys use and like VFD and I can see lots of advantages.  I am not an electrical type person and not familiar with VFD programming so I went with the old tried and true that I know.

D


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## ErichKeane (Apr 13, 2020)

Twirpunky said:


> If all you want is simple single to three phase, why not use a rotary phase converter?  I bought a panel from phase-craft (no longer in business) for around $200 and used a 5 hp 3 phase motor I had laying around.  Cheap, easy, and durable as heck.  Several companies sell panels.  I wish phase-craft still sold panels.  They were very well constructed and worked great.  Lots of guys use and like VFD and I can see lots of advantages.  I am not an electrical type person and not familiar with VFD programming so I went with the old tried and true that I know.
> 
> D


A VFD is likely significantly more power efficient than a RPC, and likely cheaper to boot.

The additional features of a VFD are nice as well. I can change my mills rpm with a small knob rather than a belt change, and my lathe without swapping pulleys.

 The "programming" comes down to just punching in a couple of numbers to tell it about your motor and what you want the switches to do. For basic operations it is really quite easy.


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## Twirpunky (Apr 13, 2020)

opps!!  posted twice


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## Twirpunky (Apr 13, 2020)

Actually, I was responding to the Original Post. "VFD as a basic phase converter".  Yes, I can see lots of advantages for some people using a VFD but for others, like me, the RPC was the way to go.  I can run multiple 3 phase machines all off one unit and didn't have to deal with control circuits and other motor needs like coolant motors.  Just plug em in and run em.  All for less than $200.


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## Aaron_W (Apr 13, 2020)

We are lucky to have several experienced VFD people on the site who work with VFDs in their day job, not just hobbyists who have installed a few in their own shop.


If you have decided to go with a name brand, I had good luck with Wolf Automation when I bought mine. Their tech support has been responsive and was helpful in helping me decide on which VFD to get for my mill. If you are paying for name brand it makes sense to me to get it from a place that can help you instead of some Ebay seller.

Marshall Wolf Automation


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## matthewsx (Apr 13, 2020)

So, like I said before if it has the right input and output it will do what's needed. I originally bought one of the cheap ones from eBay for my lathe but wasn't happy with it (really didn't know squat at that point, just it wasn't what was advertised and smelled vaguely like burnt electronics).  My lathe doesn't have any electronic controls so it was really just to power the 3 phase Baldor motor I bought.

I then purchased a TECO VFD from a reputable supplier for my application and was able to work out a partial refund from the eBay seller. Later I got into my mill/drill project and had the cheap unit sitting on the shelf so I decided to use it. I still haven't gotten it talking with my controller but that may just be my lack of expertise rather than the VFD. It does drive my spindle though and it's nice to have around the shop as a spare if needed, you never know when a nice 3 phase tool will show up and need power

If I was buying a brand new lathe and retrofitting it with the stock control panel I would spend the extra money to buy the recommended unit from a known source with support. You might not need it but it's great when it's there if you do, I'll probably end up doing that for my CNC mill/drill once I get the new control box built.

I'm assuming the PM purchase was decided for similar reasons and ultimately $200 one way or another is chump change in this hobby (I just spent almost that on a new compound casting for my tiny Craftsman lathe).  In fact, during these challenging times it will actually make you feel good to buy from an American supplier that's keeping it's workforce employed rather than an eBay seller that just drop ships.

Aaron is right about this forum, we have people here who know this stuff, and CNC, and tooling, and everything else. Passionate hobbyists who just happen to do it for a day job too, thank you for being here 


Cheers,

John


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