Need Help With Decision on New Lathe and VFD

It is pretty much the same as the PM-1440GT (it is the same manufacturer, the specs are vendor specific). I would go with the basic VHD 1440GT wiring directions posted previously. The directions are based on using the WJ200-022SF VFD, it can be purchased from Eisen or https://www.driveswarehouse.com/ . You will need a braking resistor, this and VFD enclosure suggestions are in the attached document, availability my be different in Canada. This is a general guidance as well as the suggestions for the basic VHD1440GT wiring directions. If you are unsure on any of the electrical's, get an electrician to check your work. Also in Canada, there are different code requirements, if I recall they require a power disconnect at the machine/VFD enclosure along with proper fusing.

I am constantly tweaking the VFD parameter files, when you get ready to program the VFD, send me a PM and I will send the current iteration for the WJ200.

Be aware that when rewiring the lathe with a VFD, the motor must be directly connected to the VFD, contactors are not used. The VFD motor output will sense overload/short conditions. The VFD input power should be fused along with a power disconnect. You need to provide 240VAC power to the lathe control box for the transformer power and for the coolant pump, but you could reduce the size of the control box fuses since they are no longer supplying power to the motor via the contactors. Single phase power to the lathe control board for the transformer per your schematic would be connected to terminals R and S which go on to connect power to the transformer. On the coolant pump power would be supplied through the contactor, you would need to see which terminals the overload relay is connected to and which coolant motor wires are connected (should be R and S).

You need a dual pole brake switch to replace the stock one, so when depressed it breaks power to the contactors and the other pole issues a free run command to the VFD. Otherwise the VFD will fight the foot brake when applied.

This all assumes you have some basic familiarity with electrical wiring and know what you are doing.

This is the PM-1440GT control board, you can see it is the same, the earlier models had a cartridge fuse holder.
system.jpg
 

Attachments

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Mark, I really appreciate your thorough replies. Thank you very much for taking the time and effort to be so helpful. The lathe won’t be shipped until April because it’s bloody cold here. In the meantime I’ll be doing all the research and preparation to be ready...including finding local electrical expertise. Anyway, I can’t thank you enough for sharing your knowledge and advice.
 
Just wanted to update anyone interested in my new lathe. I’m back from holiday and just wired the funds to Eisen yesterday. The person I always talk to, Jason, has been fantastic to deal with. He takes the time to answer all my questions and is just a nice person to deal with. My next job is to get busy and order all the stuff that Mark has recommended. I won’t take delivery for another month or so..it still looks like the middle of winter here. I’ll try to post as much as I can so people can follow along my journey. Cheers.
 
Please update us when you've had a chance to get your lathe set up and made a few cuts. The price on these Eisen's with DRO is very attractive!
 
Yes it is. Almost the identical Taiwan machine as the PM 1440GT...just minus 3 gears (which I won’t need with a VFD) and the GT’s larger spindle, which would be nice. I probably would have been very tempted to get a heavier Eisen machine if my shop was at ground level, but no such luck. In any case, I think it’s going to be a great machine.

There is still quite a bit of snow where I’m at. I won’t pick it up from Montana shipping outlet until the snow is gone. Then I have to get it into the basement (ugh)....and think it will take a while to get it rewired. I’d love to give you an update much sooner, but it’s a big project for me. I’m building a spreadsheet with everything I’m going to need, vendors, costs, notes etc. to do the rewiring/added components. I’ll share that once I’ve had it validated. So far my experience with Jason at Eisen has been great. Very nice/helpful so far.
 
Yes it is. Almost the identical Taiwan machine as the PM 1440GT...just minus 3 gears (which I won’t need with a VFD) and the GT’s larger spindle, which would be nice. I probably would have been very tempted to get a heavier Eisen machine if my shop was at ground level, but no such luck. In any case, I think it’s going to be a great machine.

There is still quite a bit of snow where I’m at. I won’t pick it up from Montana shipping outlet until the snow is gone. Then I have to get it into the basement (ugh)....and think it will take a while to get it rewired. I’d love to give you an update much sooner, but it’s a big project for me. I’m building a spreadsheet with everything I’m going to need, vendors, costs, notes etc. to do the rewiring/added components. I’ll share that once I’ve had it validated. So far my experience with Jason at Eisen has been great. Very nice/helpful so far.
BB, I too just purchased the Eisen 1440E 3ph single speed, I've been following your convo with Mark and the wealth of information he has shared with you...Post some pictures when she arrives, Im waitng for another 2 weeks for mine.
 
Lucky Liverider, you made a wise purchase decision. . I’ll definitely be posting pictures as I go through the process.
Mark is very popular on these boards and it’s obvious why. He’s been very, very helpful to say the least. I also picked up some great ideas from jbolt’s thread on his 1440GT build. I’m really looking forward to getting this machine...Im sure it’s going to be really nice. Lots to do before It makes chips though. Good luck with yours. I’ll be watching your posts.
 
Just a quick question - Do you have 3 phase available? Residential areas and many farms only have single phase. Industrial areas have 3 phase in Alberta.
 
"Inverter Duty" or "Inverter Rated" is a marketing term. Ignore it. You will spend hundreds of dollars for this term. All modern three phase motors will handle power supplied by a VFD with no problem. Especially on a small hobby lathe.
 
There is inverter duty or rated, and what is known as inverter/vector motors. There are some differences depending on the application. Typically inverter rated motors have a higher voltage/temperature rating for the internal motor wiring, so less susceptible to insulation breakdown which can occur with the voltage spikes generated by the VFD's. This is also exacerbated with very long motor cables. The issue why this is not really a factor for most non-inverter rated motors is that most are dual rated for 230/460V and wiring insulation is already rated at something like 1000V. If you a running the motor at 230V with short motor cables, it pretty much is not a problem. This may only be an issue with older motors say 20+ years old or working under extreme duty/temperature where the insulation is deteriorating. Lowering the carrier frequency in older motors diminishes the spikes, one can also use an inductor/reactor which also decreases the spikes and smooths the voltage. Most newer 3 phase motors are designed with high voltage/temperature insulation magnet wire, I believe it is something in the 1000-1500V range. Many newer 3 phase motors are inverter rated at no additional cost, i.e. they are using better insulated magnet wire.

On a separate note, there is a difference in how motors will perform (torque and Hp) over a designed speed range and also a maximum RPM that motors are rated to. You will often see a CT (Constant toque) rating on motors and this is the speed range that the motor will maintain constant torque below a base speed (60 Hz). Older 3 phase motors this may be 2:1 so the constant torque would be 30-60 Hz, an inverter rated motor it is typically 10:1 so 6-60 Hz, and inverter/vector motor it is 1000:1 or higher so full torque down to 0 Hz. So if you are operating the motor down to say 15Hz, you would be better off with an inverter rated or vector motor. On the Hp end, inverter rated 4P motors are typically good to run up to 120 Hz (2X) their base speed, but Hp will often diminish above 90 Hz. A true inverter/vector motor maintain full Hp typically to their maximum speed which is around 3X their base speed.

Last but not least their is motor cooling issues, TEFC motors have a fan attached to a back shaft. The fan air flow is speed dependent and efficiency of cooling becomes an issue outside of an operating range of ~15-90 Hz. Dedicated inverter/vector motors are typically TENV (no fan) or TEBC (separate electric fan) so cooling is not an issue over the full speed range.

Performance wise if you are using the motor over a narrow speed range of around 20-80Hz, you won't see much difference, operating over a wider speed range, the difference is much more significant. On mills and lathes with factory VFD systems, the motors are often operated over a 10 fold speed range, so my mill motor operated from 20-200 Hz. This would be a problem for a standard motor. Also speed stability of an inverter/vector motor I have found to be better than a non-inverter motor, but a non-issue in most applications.
 
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