Minimal VFD setup for PM-1440GT (or similar)

[AlanB]

I'm considering a lathe upgrade here, at the moment my favorite candidate is the PM-1440GT 3 phase. I want a VFD and don't have 3 phase power, so the lathe will not be usable at all until the VFD is working. The recommended VFD is the Hitachi WJ200-022SF.

So the goal is to plan a VFD configuration for initially operating in the simplest way, with minimal intrusion into the lathe's factory wiring (and easily restored to stock factory condition). Delay any "non essential extra feature" options to separate future upgrade(s) to keep the initial setup as simple as possible (KISS). Carefully document the wiring and changes for maintenance and future upgrades.

I've looked at a lot of other folks plans here and elsewhere on the web and gone through most of the Hitachi manual. This is the simplest variation I have come up with thus far.

Version A

1. Physically locate the VFD where it can be accessed to set speed and adjust programming easily. Use an enclosure with a hole so wiring is protected but front panel is out where it can be accessed without risk to hazardous voltages. The input circuit breaker can be similarly mounted in this same box.
2. Install the power cord and plug to bring 220V and ground to the appropriately rated circuit breaker, then to the lathe (on the appropriate two of the three input busses) and to the VFD power inputs.
3. Run motor power wires from the VFD motor outputs to the motor, disconnecting and insulating the original motor power wires.
4. Program the VFD for the motor ratings and perform basic testing as directed in the VFD manual to verify the VFD and motor wiring.
5. From the 24VAC coils of the forward and reverse motor direction contactors parallel a pair of small 24VAC coil control relays, the output contacts are wired to the appropriate VFD run (forward and reverse) inputs. These modules can be mounted in the VFD enclosure as well to minimize changes in the lathe itself.
6. Program the remaining desired parameters into the VFD for basic operation.

This would get the lathe up and running with a single enclosure that could be fabricated before the lathe arrived. No major rewiring of the lathe is required. The front panel of the VFD can be used for setting motor speed (or a pot added for a little more convenience at the cost of some additional wiring). The lathe controls would operate as normal. More additional features could be added, but this seems to be the essential minimum, and a quite adequate starting point.

I'm interested in comments and feedback.

Thanks in advance.

 

[mksj]

The easiest way I would suggest is to do the basic VFD install that is outlined at the end of this thread for the most current version. I believe QMT may also have a similar document. There are also other documents specific to the VFD enclosure and recommended components. These days I recommend people go with a slightly larger VFD cabinet and omit the fan cooling to simplify the build. Fusing is optional. In your case, sure you can have a 24VAC relays in parallel with the respective contactor coil wiring if you want to keep it bone stock. I would remove the stock motor cable at both ends or just remove it completely as it is easily reinserted. I typically put the speed pot in a tach housing mounted on the headstock or under the DRO.

PM-1440GT Basic Wiring Changes for using the Contactors to switch the VFD inputs

I previously outlined the use of new contactors to use to switch the VFD inputs when doing a basic 3 phase VFD lathe conversion, this retains the same functions (and interlocks) as the stock lathe and should operate the same. The VFD adds speed control, and acceleration deceleration control. In...

www.hobby-machinist.com

 

[AlanB]

Thanks for the response.

 

[AlanB]

Were there some recommendations for a cabinet for the VFD and main breaker?

 

[mksj]

See attached, I would recommend a 16x14x8" enclosure if no fan, might be able to get by with the next smaller size if minimal components, but check the height of the braking resistor so it fits. VFD is over 7" depth so need the cabinet depth to be 8", also the VFD should have about 4" space above and below it. Some of the links in the document may be older ones, you can search the part numbers. Automation Direct has some new power disconnects also WEG which are very reasonable. A lot of places are out of stock, so may need to hunt the electronic part houses or eBay.

https://www.automationdirect.com/adc/shopping/catalog/circuit_protection_-z-_fuses_-z-_disconnects/disconnect_switches/merz_non-fusible_disconnects_-a-_manual_motor_controllers_(ul_508)/door_mount_(16-63_amps)?searchStatus=bad

WEG Electric Disconnect Switches – State Motor & Control Solutions

Shop for WEG Electric disconnects from State Motor & Control Solutions. Count on us for expert service, fast response times & same-day shipping.

motorsandcontrol.com

 

[AlanB]

If the front panel of the VFD is to protrude through the enclosure cover should the box be shallower? Or use 8" and build up the base of the VFD appropriately?? I want to be able to access the VFD controls as well as see it, so a window is not sufficient.

 

[Steve R]

I have a 1440TL and this is what I had done. The back of my lathe is NOT up against a wall. I mounted the enclosure on the back and used a 6ft range cord to go from the plug-in on the wall into the enclosure, to the disconnect switch, disconnect switch to the vfd. The power out of the vfd to the power in terminals on the lathe control board, wires ran through the conduit. I purchased the Hitachi OPE-SRmini & the 4X-KITmini to mount the OPE-SRmini. The OPE-SRmini is connected to the VFD by a regular network cable (RJ45 ends, straight through not a null-modem) The OPE-SRmini allows you to operate the vfd without actually having to touch it. There is a jack on the vfd, just remove the cover to gain access and plug the cable in.

On the vfd you go into the programming and I had to change these
b037 = 00 (unlocks the programming)
b012 = motor current. look on the motor plate for the amp rating. I read were they recommended 1.25 to 1.5 times amp rating on plate
a002 = 02 if you are going to press the run key on the vfd or 03 if you use the OPE-SRmini and use the run key from there.
f001 = set your frequency (I set mine at 60)
h004 = set the motor poles (see plate on motor)
a001 = 00
f002 = acceleration time (I set mine at 2.0)
f003 = deceleration time (I set mine at 2.0)

With this setup, I turn on the disconnect switch on the enclosure, press the green run button on the remote display, make sure the frequency (display) is showing 60 (turn poteniometer). Once the frequency is set it doesn't change unless you change it. At this point you don't want to change the frequency much because you are just using the vfd to convert single phase to 3 phase power. All the ectronics in the lathe control panels has not been touched and works just as if you had 3 phase utility power. I may in time switch over to a more intergrated vfd controls but for now I just want to be able to use the lathe was built and make sure everything was working before doing a conversion.

I have this same setup and programming on my 949TS mill and I do adjust the frequency there ocassionally to adjust the motor speed. However they is no other electronics on it.

 

[AlanB]

Very nice setup. Interesting to have the controls on the edge of the box. That might be good for my situation as well. Don't have a lot of space to work with.

 

[matthewsx]

I suspect you'll find that operating the VFD from it's onboard controls is sub-optimal. It seems like it would be easier but most often they have little buttons and knobs and smallish displays. While you have to access them for setting things up it's a lot nicer to have large buttons and controls programmed to do exactly what you need them for.

You should be able to get to some good surplus houses in the bay area that have used industrial controls available for cheap. There's nothing like the feel of an Allen Bradley control switch to inspire confidence when operating a machine tool. The slight extra effort to build a professional control panel is insignificant compared with the ease of use you will enjoy from doing it right. I've done it both ways, with custom controls on my Seneca Falls lathe and just running from the VFD control panel (formerly) on my mill drill. Trust me, you won't regret going the extra distance.

John

 

[AlanB]

Thanks for your comments John. I'm sure you are correct.

The minimal configuration I'm considering is to get things going quickly - I'd like to have a new lathe up and running within a few days of arrival. Ideally the VFD box will be pre-built and there will only be three cables to attach to the lathe. I can't be without the lathe for very long, and I don't have enough space to keep the old lathe. So the new one will need to be operational quickly. I plan to upgrade things further later on, I can schedule a few days of downtime but I can't have the lathe offline for more than a few days. Many people seem to think that a VFD setup must be complicated, but the complexity appears to be caused more by other "requirements" and "features" that a VFD empowers, rather than anything essential. I plan to do more, I just want a concrete simple plan to get started with. The only control I have on my existing lathe is an on-off switch and a speed knob, aside from belt (and gear) changes, and it has served me quite well for a long time (though I want to do more, otherwise why upgrade). I probably will do a speed pot rather soon, perhaps even before the lathe arrives as that is a very simple thing to do and I do need that for one operation that I use the lathe for. What I don't want to do is start a major rewire of a perfectly good brand new under-warranty lathe before I can even turn it on the first time. I think many new lathe purchasers are in a similar situation.

Even with the minimal configuration "A" above the lathe controls will all work normally. Forward/reverse, Jog, the foot brake and the anti-restart feature. The only thing requiring front panel control is the speed setting (and that's not a feature that the lathe came with). If the pot is implemented (a simple upgrade) then there is even less need for using the VFD front panel. However I would like to be able to adjust various settings and I expect to need to "tune" the program settings from time to time, especially at the start. I don't want to have to contort into some difficult to access panel to do programming adjustments, or have to get the laptop to change a parameter. I don't expect the programming to be perfect at the start, there are too many options and features.

Incidentally most of the surplus houses are gone, and with Covid any left are probably closed, if they even survive. The ones close to my location are long gone, and the others I was aware of are a long way away and are probably gone also. So we're pretty much stuck with the same internet sources as everyone else.