VFD Questions

[Oceaniron]

Hello MKSJ,
I plan to purchase the PM1440GT lathe with the 3PH 3HP motor option. I am also considering using a Yaskawa CIMR-VUBA-0012-FAA VFD to control the motor rather than the Hitachi WJ200 VFD. The Yaskawa is designed to accept single phase input of 240 VAC and convert to the 3PH output and is rated for the 3HP motor. Other than the higher cost can you think of any reasons why I should not use the Yaskawa in this application. Also, I have attempted to attach the Yaskawa drive manual to this post however I am not sure if it attached. Thanks Steve

 

[Oceaniron]

I see that the attachment did work.

 

[MikeInOr]

A recent thread concerning "DRO drift" due to VFD noise got me wondering about VFD's in general. A quick visit to Wikipedia revealed they're not quite as straightforward as I had thought. There are six different circuit topologies (not counting hybrids), with the most common being the so-called VSI -- "voltage-source inverter", with PWM outputs. Variations in that category include open loop and closed-loop speed control. An "interesting" potential issue with VFDs is mentioned -- high currents flowing through the motor bearings due to the PWM high frequency drive leaking into the hardware due to capacitive coupling. This can lead to premature bearing failure. The article also mentioned separating VFD drive cables from other electronics by at least 50cm (that's over 19 inches).

So the questions:

1. I'm wondering what sort of VFD people are installing on their machines. Open loop control or closed loop?

Open loop. Never had any need to keep super tight RPM tolerances on a machine tool.

2. Are the motors also replaced with ones that are designed for use with a VFD? Synchronous? Induction?

About 8 VFD's so far. All running the original motors. Most are quite old motors with only a couple from the past half century.

3. Has anyone experienced bearing failure in their motor(s) after upgrading with a VFD?

Nope! Not me!

4. How troublesome has electrical noise been after the upgrade?

See my comment on my lathe below which I added extra isolation for minimize interference with my DRO. I have never had RF noise issues from my expensive or cheap Chinese VFD's.

Thanks!

My first VFD is 15+ years old now, a Fujitsu. I have never had any issues with it running the 1947 16" 7.5hp radial arm saw I purchased it for. I have several others now, both name brand (Fujitsu, Hitachi, Teco, etc.) and generic Chinese. I can't really tell the difference between them once they are wired up and working. I have never had any issues with bearing problems although I was VERY concerned about blowing up an irreplaceable 75 year old RAS motor initially.

I remember reading the same information before purchasing. None of them ever amounted to any issues for me. I think most of those claims are from small shops selling rotary phase converters and from the legal department of large VFD manufactures to CYA themselves from damage to multimillion dollar machines being blamed on the manufactures VFD. (We said there is a possibility of problems so we deny all liability.)

For my lathe I used shielded power wires between the VFD and the motor and shielded control wires. I also used a filter similar to this: https://www.ebay.com/itm/401264619208?epid=27007372697&hash=item5d6d3c2ec8:g:AC0AAOSwMWdddEOr in front of the VFD to minimize rf noise being injected back into the AC line as I was worried about my DRO. In this configuration I have never had any problems. I paid extra for a Hitachi VFD for the lathe in the hope that it might produce less noise being a named brand and also better manuals and support. I have no idea if these extra precautions made any actual difference to me or not... I have never had a problem with my lathe or DRO on the lathe.

 

[mksj]

Yaskawa V1000 is a very good VFD, it is probably the most common brand VFD used in factory supplied machines in manual lathes and mills 5 Hp and under. I use the V1000 in both my lathe and mill, the programming is quite a bit different and also the inputs are programmed differently than the WJ200. The software interface is a bit better than Hitachi, but requires on to make an RJ45 to RS232 to USB cable.

Had another person who did have some noise issues with his DRO glass scale which appeared to be from the VFD. I recommended a VFD line filter, just before the VFD input and some toroids on the output motor wires. I do use line and toroid filters on both my mill and lathe, have not had any issues with electrical noise, all the cables are shielded. Below were my suggestion for pre/post filtering for electrical noise.
https://www.onlinecomponents.com/en/te-connectivity-corcom-brand/25fc10-11162193.html
https://www.mouser.com/ProductDetail/United-Chemi-Con/LRF251515MKCX?qs=DPoM0jnrROXqC3mtdV19hA==

 

[MikeInOr]

Hello MKSJ,
I plan to purchase the PM1440GT lathe with the 3PH 3HP motor option. I am also considering using a Yaskawa CIMR-VUBA-0012-FAA VFD to control the motor rather than the Hitachi WJ200 VFD. The Yaskawa is designed to accept single phase input of 240 VAC and convert to the 3PH output and is rated for the 3HP motor. Other than the higher cost can you think of any reasons why I should not use the Yaskawa in this application. Also, I have attempted to attach the Yaskawa drive manual to this post however I am not sure if it attached. Thanks Steve

The Hitachi is well known on this board and throughout the internet with good documentation. My lathe was my most complex VFD install so the WJ200 was well worth it to me (I scored three 5hp rated WJ200's used for cheaper than Chinese VFD's).

I have not used a Yaskawa VFD. If the documentation on the Yaskawa is very good, has the capabilities you want (controls, braking, reversing, etc.) and is considerably cheaper I would go with the Yaskawa. If the VFD is going to be installed by PM I would worry evan less about the documentation and support on the Yaskawa.

 

[Oceaniron]

Thankyou Mike. I most likely will go with the Yaskawa VFD even though it costs more than the Hitachi. I plan to do a second Yaskawa VFD on a 5 HP mill rebuild so it will be less work to have both the VFD's of the same type.

 

[Oceaniron]

Thankyou MKSJ.

 

[B2]

I have the 3phase PM1440GT and converted it via the Hitachi WJ200 VFD. The conversion seems to work with out any problems. I used no EMI filtering and see no ill effects so far. I see no issues with my near by equipment, including the DROs. I think the steel enclosures of the 1440GT and short cables to the motor helps to isolate the motor EMI significantly. I also used 2 - 8 conductor shielded cables to the front panel, but the other wiring to other parts of the lathe uses the standard cables supplied with the 1440GT. I am still using the factory original 3ph motor, which is a lower cost inductive technology and not designed for variable speed. It works reasonably well for me and can be run at very low frequency if one desires. Once running it seems smooth at all frequencies, but some have reported acceleration issues for frequencies well below 60Hz. I might change it to a motor designed for variable speeds some day, but for now it works for me. My VFD conversion is totally solid state...I have removed all of the mechanical relays leaving room in the rear enclosure for everything including my home made 400Wx50 Ohm braking resistor stack. The braking resistor stack sits right next to the VFD and this may tend to localize its EMI. By the way, the 400W is way over kill for this application. I ran a dozen high RPM start-stops, using the three jaw PM chuck as the load, as fast as fast as I could and used the finger test on the braking resistors to determine temperature change.... the resistor just started to warm up. I'll attache a photo with some notation. I suppose the hardest part of the conversion was figuring out how to make all of the wiring connections. With all of the features that others, especially Mark, has suggested the number of wires in and out went up significantly over the factory build. I think the conversion does everything and maybe a couple of others, that has ever been discussed on HM. I am finally starting to write up the conversion, but I am trying to write it so that an HM can figure it out. So, taking my time.

Dave

 

[B2]

Hello MKSJ,
I plan to purchase the PM1440GT lathe with the 3PH 3HP motor option. I am also considering using a Yaskawa CIMR-VUBA-0012-FAA VFD to control the motor rather than the Hitachi WJ200 VFD. The Yaskawa is designed to accept single phase input of 240 VAC and convert to the 3PH output and is rated for the 3HP motor. Other than the higher cost can you think of any reasons why I should not use the Yaskawa in this application. Also, I have attempted to attach the Yaskawa drive manual to this post however I am not sure if it attached. Thanks Steve

Hi @Oceaniron ,

Finally finished my documentation of my VFD conversion on my PM1440GT. I think my machine is pretty much the same as the one you are getting. It came with the 3PH 3HP (2.2Kw) motor. I used the Hitachi VFD, which just fit. I got everything in the rear of the lathe stand without a external box. You might find it useful.

VFD conversion via solid state electronic components. PM1440GT, VFD, 3-phase

VFD conversion using solid state electronic components. I finally finished documenting my PM1440GT lathe VFD conversion and want share it. It took me longer to write this up than it did to actually build the new electronics! (Are these sorts of things every really finished?) I apologize...

www.hobby-machinist.com

I did not put any line filters in but there is plenty of room to do so. I do not seem to have an problems with noise on the line. This maybe due to my layout.

Dave

 

[mksj]

FYI, Yasakawa has a new series (GA500) of VFD's which appear to be a replacement for the V1000 series whihc is available in single phase models up to 5 Hp. I am currently building a control system for an ERL-1440 with the 5 Hp GA50UB018ABA which is a beast. Programming appears to be very similar to the V1000 and they use a USB cable interface to use their software, and their software is more user friendly than the Hitachi. The V1000/GA500 have a few more programming features than the WJ200, but both are very good reliable VFD's. The 3 and 5 Hp models are indicated below, pricing can vary quite a bit as well as inventory. Also some of the sites may offer pop-ups with additional discounts, some have free ground shipping. I can help with suggested parameter files if someone decides to use these.

GA50UB012ABA 1/PH 240V 3.0 HP 12.2 AMPS ND 11 AMPS HD

https://www.precision-elec.com/shop/ga50ub012aba/

YASKAWA GA500 INDUSTRIAL AC MICRODRIVE MODEL# GA50UB012ABA 1/PH 240V 3.0 HP 12.2 AMPS ND 11 AMPS HD – IN STOCK AVAILABLE NOW

AVAILABLE NOW

prbelectronics.com

GA50UB018ABA 1/PH 240V 5.0 HP 17.6 AMPS HD

https://www.precision-elec.com/shop/ga50ub018aba/

YASKAWA GA500 INDUSTRIAL AC MICRODRIVE MODEL# GA50UB018ABA 1/PH 240V 5.0 HP 17.6 AMPS ND

STOCK IS SUBJECT TO CHANGE WITHOUT NOTICE. THIS PRODUCT HAS EXTENDED LEAD TIMES, CONTACT US FOR ESTIMATED AVAILABILITY DATE.

prbelectronics.com