# Strange issues with a Powerflex 70



## mikey383 (May 21, 2012)

Long story kinda short, our customer has been having issues with a filler pump's drive faulting out during CIP. Powerflex 70, 7.5hp, 11A drive. The problem then migrated its way into production. They ordered a new drive, motor and gearbox, and decided to change them all. The new motor is a 480V, 7.5HP, 9.3FLA, 9 lead motor, same as the old motor. I did not wire the new motor, one of their maintenance guys did, and he also wired the drive. 

This is where I come in. I verified all the settings of the old drive were copied to the HIM, then imported to the new drive, and verified it was wired correctly. 

So we go to start up the machine, the drive is running fine at 13Hz, 5.8A, but the motor is running backwards. I change the rotation by swapping motor leads on the output of the drive, and it goes into "current limit" at 0Hz, 10.5A. Swap them back, and the drive runs fine, but still backwards. Swap them at the disconnect, and it goes in to current limit mode again. So I swapped them back. Checked continuity between legs on the motor, everything looks like it should. 

I then put the drive into reverse, and everything runs fine. The motor is going in the right direction and they now have product flow. The drive shows 13Hz, 5.8A. Stop the motor, swap leads, and put the drive in forward....current limit, same as before. Swap them back, put the drive in reverse, and it runs fine. The customer said since it was running, to just leave it be for the time being. 

FWIW, the motor has an encoder tied into the drive, which from what I've gathered, only transmits the pump RPM to the filler HMI via ethernet comm module. I played around with the encoder wiring, and get the same result no matter what I do. Since the motor is running fine when the drive is either in forward or reverse with the way it's currently wired, I don't believe this to be an encoder issue.

Any ideas? I walked away after a 14 hour day just scratching my head.


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## JRaef (Mar 23, 2009)

mikey383 said:


> Long story kinda short, our customer has been having issues with a filler pump's drive faulting out during CIP. Powerflex 70, 7.5hp, 11A drive. The problem then migrated its way into production. They ordered a new drive, motor and gearbox, and decided to change them all. The new motor is a 480V, 7.5HP, 9.3FLA, 9 lead motor, same as the old motor. I did not wire the new motor, one of their maintenance guys did, and he also wired the drive.
> 
> This is where I come in. I verified all the settings of the old drive were copied to the HIM, then imported to the new drive, and verified it was wired correctly.
> 
> ...


Sounds as though it is a quadrature encoder, meaning one that reports it's direction of rotation, and when someone set it up in the drive, the rotation was opposite of what it needed to be, according to the drive. Take a look at parameter 412 and report back what it says. If it is set to a "0" or "1", then the drive is looking for a quadrature encoder, which you would typically use in Flux Vector (FV) control. If all they want is a reporting capability and the direction is assumed anyway, that should probably be set to a "2" or "3", meaning a basic single channel encoder, and 

But if so, there may be another issue: if this is a *centrifugal *pump, and they put the drive in FV control mode because the motor has an encoder, then they may have added complexity unnecessarily. Centrifugal pumps run almost as good on basic V/Hz control as they will under FV or even SV (Sensorless Vector) control. Take a look at parameter 53, it should be set to "3" if it is a centrifugal pump. If it is a Positive Displacement pump, that's a different story and you may need to have a discussion with whomever designed this. But IF parameter 53 is set to anything other than "3", then you would have also had to perform an "Autotune" procedure (par. 61) because it is a new motor. Copying the old parameters would not be good enough, the VFD has to learn the particulars of this specific motor to function correctly in SV or FV control.


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## mikey383 (May 21, 2012)

Thanks, JRaef. 

I'll do my research tomorrow morning, and let you know what I find.


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## RIVETER (Sep 26, 2009)

How did you "play around with the encoder wiring"?


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## mikey383 (May 21, 2012)

RIVETER said:


> How did you "play around with the encoder wiring"?


I swapped the A/A', and B/B'. No matter what, the drive acts the same. 

It will run fine in forward or reverse, but if I swap the motor leads, it goes into "current limit".


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## RIVETER (Sep 26, 2009)

mikey383 said:


> I swapped the A/A', and B/B'. No matter what, the drive acts the same.
> 
> It will run fine in forward or reverse, but if I swap the motor leads, it goes into "current limit".


In the panel have you traced the encoder leads and made sure that they are not running parallel to the 480?


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## mikey383 (May 21, 2012)

RIVETER said:


> In the panel have you traced the encoder leads and made sure that they are not running parallel to the 480?


They're actually in a separate conduit. Completely separate from the 480.

Like I said in the OP, I don't believe this to be an encoder issue, since it will run either forward or backward on the drive. The problem only occurs when I swap motor leads.


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## RIVETER (Sep 26, 2009)

mikey383 said:


> They're actually in a separate conduit. Completely separate from the 480.


BUT, how about "in the panel"?


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## mikey383 (May 21, 2012)

RIVETER said:


> BUT, how about "in the panel"?


I pulled the encoder cable out of the Panduit tray and went straight from the conduit to the drive, with no luck. And as I've said, the encoder has nothing to do with the motor other than RPM feedback to the HMI. 

From what I understand, the HMI writes the speed to the drive, and the HMI reads the speed from the encoder. 

The encoder is there just for a RPM reference.


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## mikey383 (May 21, 2012)

The only thing I can think of is that the guy that wired the motor, wired it in such a way that it will only run the way its wired. Like maybe having some T leads wired in a funky configuration that it actually works in one way but not another? 

I know that's a stretch, but that's all I can speculate at this point...I guess I'll find out tomorrow.


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## guest (Feb 21, 2009)

mikey383 said:


> The only thing I can think of is that the guy that wired the motor, wired it in such a way that it will only run the way its wired. Like maybe _*having some T leads wired in a funky configuration that it actually works in one way but not another? *_
> 
> I know that's a stretch, but that's all I can speculate at this point...I guess I'll find out tomorrow.


I'll bet that you will find the motor's leads ARE miswired. Verify that they are correct before you burn up the new motor. :thumbsup:


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## Jhellwig (Jun 18, 2014)

0hz and current limit is in the wiring or mechanical. I also suspect that some parameters got changed that shouldn't have. Might be worth defaulting the drive and starting from scratch on the program.


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## 51360 (Jun 9, 2014)

Morning:

Might be important to know why the original drive was faulting. If you started from scratch, was everything verified. For example, insulation tests on feeds etc.

Just curious what type of process this is? In my mining days, CIP stood for carbon in pulp.

Borgi


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## xpertpc (Oct 11, 2012)

Besides being a communications protocol, CIP usually means "Clean In Place" most times in the food industry that puts the system through more aggressive use then normal production would. Slugging the pumps with high volumes of water and slamming valves repeatedly.

He said it started in the CIP cycle then progressed into the production cycle.


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## 51360 (Jun 9, 2014)

xpertpc said:


> Besides being a communications protocol, CIP usually means "Clean In Place" most times in the food industry that puts the system through more aggressive use then normal production would. Slugging the pumps with high volumes of water and slamming valves repeatedly.
> 
> He said it started in the CIP cycle then progressed into the production cycle.


Ok, thanks " expertpc ". 

Years of experience with drives, but not in the food industry. My bad! 

I'll watch and learn.

Borgi


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## JRaef (Mar 23, 2009)

There is no way to miswire an AC induction motor so that it causes a drive to go into current limit when the rotation is swapped. However, if the drive is expecting to see one direction of rotation, and the encoder tells it the polar opposite, then the drive has to assume the motor must be overhauling, and depending on the stop method in programming, might be attempting to brake it to a stop, or if Flying Start is enabled, it is attempting to reverse it and since it isn't really reversed, it just locks up. The actions actually are difficult to predict in that it's something that is no supposed to happen in the first place.


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## mikey383 (May 21, 2012)

Got it taken care of. Consulted one of our top electricians this morning and found that the encoder was backwards in regard to rotation. I swapped the B and B' on the encoder wiring, swapped motor leads and it is working correctly with the drive in forward. I was swapping both A and B, which apparently does nothing. The encoder does more than what I originally though from my brief lookover. I don't have much experience with this particular machine as it's only a few years old and really hasn't had many issues, and I have very limited experience with encoders. 

I did not do the initial troubleshooting, but I wonder if the original encoder may have been the problem all along. I don't know what kind of faults they were getting before, so I'm just speculating here. I guess I'll find if the entire problem is solved when they CIP later in the week. I was told they were having issues with the product weight fluctuating, which isn't happening now. 

Thanks everybody!


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## xpertpc (Oct 11, 2012)

....


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## McClary’s Electrical (Feb 21, 2009)

So jareaf was right in his assumptions?


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## mikey383 (May 21, 2012)

mcclary's electrical said:


> So jareaf was right in his assumptions?


Yes, he was. I'll happily eat that crow. 



JRaef said:


> There is no way to miswire an AC induction motor so that it causes a drive to go into current limit when the rotation is swapped. However, if the drive is expecting to see one direction of rotation, and the encoder tells it the polar opposite, then the drive has to assume the motor must be overhauling, and depending on the stop method in programming, might be attempting to brake it to a stop, or if Flying Start is enabled, it is attempting to reverse it and since it isn't really reversed, it just locks up. The actions actually are difficult to predict in that it's something that is no supposed to happen in the first place.


I really didn't think it was possible to wire a motor in such a manner, but with my brain being fried after a long day, I had myself second guessing. I was expecting to go home after an 8 hour day, but half an hour before quitting time, I got called to work on this problem and ended up staying much longer than anticipated.


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## JRaef (Mar 23, 2009)

mikey383 said:


> Yes, he was. I'll happily eat that crow.


No crow being served, I'm just glad it helped (if it did) and that you found the issue.



> I really didn't think it was possible to wire a motor in such a manner, but with my brain being fried after a long day, I had myself second guessing. I was expecting to go home after an 8 hour day, but half an hour before quitting time, I got called to work on this problem and ended up staying much longer than anticipated.


Been there, done that. I can't count the times when I have dragged myself through a problem that seems unsolvable into the wee hours of the night, then finally give up. I go get some sleep, then come back and realize the answer was staring me in the face the whole time. Brain cells function best when fully rested.


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## mikey383 (May 21, 2012)

JRaef said:


> No crow being served, I'm just glad it helped (if it did) and that you found the issue.


You had it nailed in the first sentence of your first reply. I just quickly scanned the logic and drive parameters, and assumed that the encoder was just for RPM purposes only. 




> Been there, done that. I can't count the times when I have dragged myself through a problem that seems unsolvable into the wee hours of the night, then finally give up. I go get some sleep, then come back and realize the answer was staring me in the face the whole time. Brain cells function best when fully rested.


Isn't that the truth. It seems like I will troubleshoot the sh*t out of something, just to go home, get some sleep, and then wake up with the answer. Extra long days are a burden on the thought process.


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## dronai (Apr 11, 2011)

mikey383 said:


> I pulled the encoder cable out of the Panduit tray and went straight from the conduit to the drive, with no luck. And as I've said, the encoder has nothing to do with the motor other than RPM feedback to the HMI.
> 
> From what I understand, the HMI writes the speed to the drive, and the HMI reads the speed from the encoder.
> 
> The encoder is there just for a RPM reference.


 
Doesn't the Plc do the processing, and the Hmi is just the interface for control ?


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## mikey383 (May 21, 2012)

dronai said:


> Doesn't the Plc do the processing, and the Hmi is just the interface for control ?


Yes, you're right. I should have worded that much differently.


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## xpertpc (Oct 11, 2012)

The powerflex can have both a local and remote HMI without the need for a PLC.


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## mikey383 (May 21, 2012)

xpertpc said:


> The powerflex can have both a local and remote HMI without the need for a PLC.


Feel free to correct me, but the HIM is the local module on the drive, while the HMI is the PanelView processed through the PLC.


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## xpertpc (Oct 11, 2012)

I posted before I saw your last response and didn't see where you had a PLC involved, people seem to use HIM, HMI, OIM, and many other acronyms for the same type of device, I just figured you were reading the speed on the local display.


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## mikey383 (May 21, 2012)

xpertpc said:


> I posted before I saw your last response and didn't see where you had a PLC involved, people seem to use HIM, HMI, OIM, and many other acronyms for the same type of device, I just figured you were reading the speed on the local display.



This is a point of confusion for me as well. It all depends on who I am talking to, and usually I end up with them physically pointing to what they're talking about.


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## JRaef (Mar 23, 2009)

While it's true that people frequently misuse the acronyms, they are actually different, and sometimes understanding the differences can help.

HMI = Human Machine Interface, a combination of software and hardware providing data and/or graphics for users as to what is going on inside of a machine process control system, such as a PLC, PAC, DCS, computer etc.

HIM = Human Interface *Module*, with _Module_ being the important distinction. That is the DEVICE that allows someone to program and/or read data in a singluar UNIT, such as a VFD or Soft Starter or Temperature Controller.

OIM = Operator Interface Module, the same as an HIM, except maybe for units that are operated by other than humans?

OIT = Operator Interface Terminal, older term used more when computers were huge boxes in another room, and the CRT screen was attached to the keyboard at a desk, but it was completely stupid without being connected to the computer.

GIU = Graphical User Interface, the graphics-only portion of an HMI.


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## 51360 (Jun 9, 2014)

JRaef said:


> While it's true that people frequently misuse the acronyms, they are actually different, and sometimes understanding the differences can help.
> 
> HMI = Human Machine Interface, a combination of software and hardware providing data and/or graphics for users as to what is going on inside of a machine process control system, such as a PLC, PAC, DCS, computer etc.
> 
> ...


Nice explanation! 

I am a little older maybe, but I have also seen:

MMI - Man Machine Interface.

Borgi


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## JRaef (Mar 23, 2009)

Borgi said:


> Nice explanation!
> 
> I am a little older maybe, but I have also seen:
> 
> ...


Comes with a risk of being accused of sexist attitudes I suppose... :whistling2:


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## STEM (Jan 16, 2015)

Whenever you're dealing with a vector drive, especially if it's doing goofy things, I recommend you always run the auto setup. Most people don't do this when they set up a drive in the first place. It makes you check essential parameters, it identifies problems like encoders that are backwards and makes you fix them or adjusts the drive automatically to rotate correctly and finally reads the motor magnetics and CEMF to optimize the performance and economy of the drive/motor.


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