what vfd to buy for closed loop control of 7.5hp Yaskawa spindle motor?

[Jim Dawson]

I'm not concerned about the budget priced Chinese VFD not working, but the question is for how long. Everyone uses the same power module, normally Hitachi, and processor, Mitsubishi I think. But failure mode is normally the capacitors. Capacitor grades are all over the map, and this is where they cut costs. I have a Hitachi VFD on the shelf that was running a 2HP Bridgeport, it just blew up one day, and it was being operated within its rated range.

I have nearly the same VFD that you have there and about the same age, a 15HP Saftronics, same as the Yaskawa, that came off of my router spindle. I used it to run my 5HP air compressor on single phase, it ran fine through the winter, but when the air temperature rose above about 70F it would go into overheat and would shut down. I replaced it with a 10HP single phase rated Huanyang and ended the problem. It's been running fine for about 8 months now, and I use quite a bit of shop air.

I would normally recommend that you use a 15HP GS3 VFD from Automation Direct, but they are not rated for single phase input. The reason that I say 15HP is because of the unusually high rated current of your motor for a 7.5HP, it's rated about 30% higher than my 10HP spindle. I'm running a GS3 10HP on my 10HP lathe spindle, but is is being powered by a very well balanced, home built, 15HP rotary phase converter.

https://www.automationdirect.com/adc...eneral_purpose The GS3 units are high quality, the tech support is great, great documentation, and they seem to be reliable. I have been using them for years. But not the least expensive.

Given your operating needs; single phase input, high operating current, some kind of decent speed control, are the reasons behind the recommendation of the Huanyang 15HP that I linked to. As a bonus they are inexpensive.

If you insist on closed loop control, then I recommend a CNC rated rotary phase or solid state converter, and a GS3 15HP VFD and purchase the encoder module with it. However the cost difference is dramatic (about 5x) just to close the loop.

But based on my experience with modern VFDs, on both mills and lathes, closing the loop for a spindle motor is not needed, the speed regulation with sensorless vector control is as good as the closed loop system. I have run it both ways and noted no difference in performance, and as I said above I do rigid tapping with my lathe on several different parts that I run.

[Al_The_Man]

I'm with Jim on this one, I have found no real difference treating Fanuc spindle motors as any common AC induction motor.
The spec on the Yaskawa appears the same.
Al.

[slodat]

Thanks guys. I appreciate the advice. I’m wondering if there’s another way to order the 15hp HY GT. Waiting until February seems excessive. Been looking around.

[Jim Dawson]

Looks like the 15HP has to come from China. Well, you can have a 10HP delivered by Saturday. https://www.amazon.com/Variable-Freq.../dp/B077KSN4C5

It would work as long as you don't get crazy with the machine. I would add a spindle load meter to the machine. I'll have to look that one up and see what I put on my machine. Not very expensive.

This is what I'm using for a load meter. There is a programmable analog output on the VFD that will wire into this meter to give you % load

https://www.automationdirect.com/adc...ters/adm100-lp

[slodat]

Jim- are you using the rated power analog out to drive the panel meter?

[Jim Dawson]

Not sure what you mean. The analog output on the VFD can be programmed to output a 0-10V signal that is proportionate to the % of maximum output current of the drive. Normally in the range of 0 to 150%, 6.6V would be equivalent to 100% output. And the meter would be scaled to read as 100% with a 6.6V input, or about 2/3 of the meter max scale.

[slodat]

I was referring to the options available to assign to the analog out. Thanks for the info. I hadn’t thought of using a panel meter for output current indication on a cnc machine. Cool idea.

[mactec54]

I've read through Yaskawa's manual for the motor. This is where I started. It states a VM3 (closed loop) vector drive, for this motor. The mill came with the G3 as shown in the photo above and this drive has no provision for encoder input.

I do see that Fuji's Frenic Mega drives has an encoder input option card. The issue I see with these drives is they have a output frequency limit of 200Hz when run closed loop vector. My motor has an encoder built in. In order to run full speed, it would need 267Hz. It did not come from the factory with a closed loop configuration with the G3 drive. I see lots of references to recommendations to run spindles closed loop.

I'm kinda lost on how to proceed. I'm concerned with the budget priced Chinese drive not working for me.

Are that explains the incorrect drive they where using for that motor yes the VM3 or VM5 should of been the drive for that motor, they just went with a cheaper drive option

We have some of these motors and the drive in stock the drives are more money most likely than you want to spend

You may be able to find a YASKAWA AC Drive-V1000 on Ebay

The Vector side of the Huanyang GT Drive has not been 100% so I would pass on that VFD Drive as being not suitable for your spindle

The only time you need to use the encoder on your motor is if you want perfect RPM regulation

[Sam_Beckham]

I was referring to the options available to assign to the analog out. Thanks for the info. I hadn’t thought of using a panel meter for output current indication on a cnc machine. Cool idea.

I think Centroid will accept that input and display a virtual load meter on the screen, at least the Oak & ALLIN1DC controls.

[slodat]

Yaskawa spec'd their GA80U2082ABM 30HP drive for single phase input operation, stating 7.5 HP/22 FLA w/o ACR and 10 HP/28 FLA w/ACR.

For three phase supply they spec'd their GA80U2021ABM 7.5HP drive stating 7.5 HP/22 FLA normal duty and 5 HP/17.5 FLA heavy duty.

I have to say all this does is confuse the process even more. 22 FLA is a lot less than the nameplate 29/39.

I'd love to hear thoughts from those of you that understand this motor/drive stuff more than I do. The difference in price between the two drives pays for a significant chunk of a phase perfect. My shop power situation is such that going to 400a single phase is a fraction of what a 3 phase service would cost. I may just go with a phase perfect, if that's what I need to do to run a spindle or two.

I really appreciate the help.

[Jim Dawson]

I have to say all this does is confuse the process even more. 22 FLA is a lot less than the nameplate 29/39.

I really appreciate the help.

I think I'm more confused than you are, 39 nameplate amps at 200V is about 10 HP. The 39 is too low to be locked rotor amps, but really too high for anything normal for 7.5 HP. I understand the two amp ratings, normally that means continuous vs. intermittent duty.

I think my 7.5 HP, 6000 RPM Haas mill spindle uses a 20 HP rated VFD and runs on single phase. I've not really been into the Haas documentation, we just make chips with it.

What is ''ACR''? I've not seen that term before.

My pleasure to help where I can.

[slodat]

Line reactor is what I believe it to be. I’ve seen reference to ac and dc reactors in various vfd ratings. I believe it is to correct for the excessive harmonics created by a single phase input to a three phase full wave bridge rectifier.

[Jim Dawson]

Ok, that makes sense.

Regarding your power: I'm running on 100 amps of 240 single phase power. Haas mill, 7.5 HP spindle running on single phase, Hardinge CNC lathe, 10 HP spindle, running on a 15 HP rotary phase converter, 3 HP cnc knee mill, VFD, single phase, 5 HP air compressor 3 phase, running on a VFD fed by single phase, + lighting. I have had all of these machines working at the same time without tripping the main breaker. So I don't think you need a 400 amp service, but no problem if you want to go there.

[slodat]

I'm already having to shut off my heat when I run my cnc router. The cnc router is 25a, vacuum table is 25a, cyclone dust collector is 25a. Add to that 22kw of heat ~92a and I'm at the 160a long time delay trip on a 200a service. I use a home automation system to disable my resistive heat when I hit cycle start on the cnc router. Adding another 160a (400a service is 80% => 320a) would allow me to run whatever I want, now and in the future. If I have to supply my bigger machines with 3 phase power, I may opt for a phase perfect over spending the money on poles and transformers for a 3 phase service. My rates go up for a 3 phase service, too.

From what I've read the motor's 39a rating is for 1/2 hour. I'm not following your math on the motor power equation.. 200v * 39a * sqrt(3) * .9pf / 745 = 16ish HP

Nonetheless.. I'm still lost on how to size a drive for this motor. I'm looking to have a reliable machine. I did order the import "10hp" drive from Amazon. Will be here tomorrow or Monday. That will at least get the spindle turning on the single phase power I have.

[Jim Dawson]

Your math is correct, mine was not.

I guess we'll see how the VFD reacts to that motor. It will be interesting to see what the actual load current is.

[slodat]

The motor nameplate current ratings are about double what one would expect them to be based on the HP rating, and Yaskawa's suggested drive 22 FLA is what a typical motor table shows for a 7.5HP 3 phase motor current.

[Jim Dawson]

The motor nameplate current ratings are about double what one would expect them to be based on the HP rating, and Yaskawa's suggested drive 22 FLA is what a typical motor table shows for a 7.5HP 3 phase motor current.

It would be very unusual but I wonder if the nameplate could have been misprinted? Your motor is very similar to my Fanuc motor and my nameplate matches pretty much what I would expect for the HP.

[slodat]

The same values are in the factory manual for the motor.

Jim- your spindle current values make sense.

[Jim Dawson]

In that case I have no idea. It will be interesting to see what the current readings are when you get that new VFD connected.

[slodat]

Lost a bit of faith in the Yaskawa tech support response.. “I based it on the 5.5KW rating of the MT3 drive that is normally supplied with this motor, I did not have the motor data available.

I can provide additional quotes for the higher amp ratings if you like.”

I sent the same nameplate photos I posted here. I’ll monitor motor current in HY 10hp drive when it gets here and report back.