# AB powerflex 525



## brightspark1

Hi guys,

I have an issue with a 1.5kw PF 525 vfd, it's giving me a fault 13 (ground fault)
I have checked the motor(OK), disconnected the motor tails completely from the vfd and tested using multi meter output terminals to ground and found no issues, yet the vfd consistently gives me this fault.

The vfd is about 2 years old installed in a climate controlled environment, is it likely the drive has just failed or have I missed something else during my tests?

Appreciate the help.


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## glen1971

Did you megger your motor leads? Each one to ground? Each one to the other ones?
Did you megger the cable from the vfd to the motor? Each one to ground? Each one to other one?

Is there a load reactor installed? Or anything else between the drive and the motor?

When I troubleshoot a motor, I'll look at the terminations at the drive first. If they look good visually I disconnect them, noting termination order, then megger them from the drive out. If a fault is detected, check the motor termination box to make sure nothing is rubbing causing the issue. If it looks good, undo the splices, noting the terminations, and megger the motor, with the internal splices done up, making sure you have a good ground connection with your megger...


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## Cow

I use the same procedure Glen does. Start at the drive and work your way out. With a megger, not a multimeter!!


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## brightspark1

I Didn't have a insulation tester on me at the time, I used the multimeter just to test the output terminals of the drive with motor cable disconnected to earth and performed diode test as well.
Even with no output connected to the drive I'm still getting a reoccurring ground fault.


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## just the cowboy

*connect a test motor*

Connect a test motor to the drive at the drive, even if it is not the same as long as it is smaller.


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## MechanicalDVR

A megohmeter is your best friend looking for ground faults. Even a cheapo is better than any multimeter.


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## John Valdes

Megging is better than a meter, but the drive is better than the megohmmeter. Sometimes better than a surge tester!
My money is on the motor.

If you can run the drive without the motor connected, you will find out in a hurry.


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## MechanicalDVR

John Valdes said:


> Megging is better than a meter, but the drive is better than the megohmmeter. Sometimes better than a surge tester!
> My money is on the motor.
> 
> If you can run the drive without the motor connected, you will find out in a hurry.


Doing factory service/start up on large HVAC/R equipment, I found way more wire damage than bad motors. Age is a huge factor.


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## JRaef

The outpuit of a VFD can produce what are called "Standing Waves" or "Reflected Waves" of higher than normal voltage, up to 2-1/2 times the line voltage. As the motor (and/or lead) insulation begins to fail, the spikes of voltage in those waves begin to leak significant voltage to ground. But a VOM is only putting 9VDC onto the circuit, it doesn't take much to stop that low voltage from registering. A megger puts a high voltage on the circuit specifically to find things like that. I suggest using at least a 1000V megger on VFD output circuits. A VOM is a waster of time for this other than to check if it is disconnected or not, or if there is a solid ground connection, which would likely be obvious for other reasons anyway.


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## Mike_kilroy

brightspark1 said:


> I Didn't have a insulation tester on me at the time, I used the multimeter just to test the output terminals of the drive with motor cable disconnected to earth and performed diode test as well.
> Even with no output connected to the drive I'm still getting a reoccurring ground fault.


There is you answer! Stop wasting time testing cables and motor!

Fault with motor cable disconnected from drive means fault is inside the drive! 

Buy a new Drive.

Sent from my SM-G900V using Tapatalk


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## Jhellwig

That is correct. Drive is junk.


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## JRaef

So for future reference, did you do a search on the A-B "Knowledgebase"? 
You have to register, but it's free (unless your domain is from a competitor, in which case you will not get in).

https://rockwellautomation.custhelp.com/

Once registered, search for document #638413

Bottom line though, you did what they will tell you to do. But if it is a 230V drive up to 5HP made in 2013, it was a known anomaly and you should contact Tech Support to discuss options.

If it is not in that size range or date code, it can also be that you are in Torque Performance Mode and Vector Control (not Sensorless Vector Control), but do not have an encoder feedback set up, or it is set up wrong. If you don't want to use an encoder, don't use that mode, change to SVC.

If it is in SVC, then it might be that you forgot to do an "Autotune" procedure. If you did, but at some time someone reset the drive parameters because they got themselves messed up in making changes and wanted to start over clean, the Autotune must be re-done. What happens some times is that someone who should NOT have been messing with the programming, does something, screws it up, panics, then resets to factory defaults and loads the programming back in with a laptop. What they didn't know is that this does not re-do the Autotune parameters. The same is true if someone changed the motor, you must re-do the Autotune, it's a different motor now.


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## mitch65

brightspark1 said:


> I Didn't have a insulation tester on me at the time, I used the multimeter just to test the output terminals of the drive with motor cable disconnected to earth and performed diode test as well.
> *Even with no output connected to the drive I'm still getting a reoccurring ground fault*.


I would think this would indicate a drive issue.


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## JRaef

mitch65 said:


> I would think this would indicate a drive issue.


Probably. 

But from my experience if a drive is looking for some sort of feedback from the motor circuit and is not getting it, how it interprets that lack of information gets very complex. This past year alone I have looked at probably a dozen or so installations where the drive does goofy things and come to find out the Autotuning was not done or re-done. Run a static tune on them and everything goes back to normal.


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## brightspark1

Thanks for all your advice everyone,
I have purchased a new drive and am going to be installing it today.


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## Mike_kilroy

JRaef said:


> Probably.
> 
> But from my experience if a drive is looking for some sort of feedback from the motor circuit and is not getting it, how it interprets that lack of information gets very complex. This past year alone I have looked at probably a dozen or so installations where the drive does goofy things and come to find out the Autotuning was not done or re-done. Run a static tune on them and everything goes back to normal.


You have some drives that really will show ground fault due to some other thing than ground fault? OK on output short fault into a motor if SVC etc is way off, but ground fault? I would suggest if you EVER see that on one of your brand drives you immediately tell the designers; that is not one that should ever get confused in the firmware - it is measured too differently. 

And if you have some drives that will give output fault of ANY KIND with no motor wires hooked to it, there is something seriously lacking in the firmware. OK, maybe missing output phase fault, but I doubt any of your brand drives offer that.

Also please clarify for me: replacing a motor with a NEW motor of exactly the same part number, your drives require re-autotuning?


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## brightspark1

Well, I replaced the drive today as well as insulation testing motor and cabling,
all worked perfectly, thanks for the help everyone. 

What component is most likely to fail on the drive to cause a ground fault?


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## micromind

brightspark1 said:


> Well, I replaced the drive today as well as insulation testing motor and cabling,
> all worked perfectly, thanks for the help everyone.
> 
> What component is most likely to fail on the drive to cause a ground fault?


Is there a disconnect switch between the drive and the motor?

If so, and it was opened while the drive was running, it's possible to blow the output transistors. It's even worse to have the drive running and then close the switch.


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## frenchelectrican

micromind said:


> Is there a disconnect switch between the drive and the motor?
> 
> If so, and it was opened while the drive was running, it's possible to blow the output transistors. It's even worse to have the drive running and then close the switch.


This is one of few most common way to destory the drive.

That why with the disconnect switch I always add a aux switch concants to prevent this mess.,,


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## micromind

One problem I have with autotune is that most drives require that the motor be disconnected from the load. Often, this is difficult and sometimes it's nearly impossible. 

I haven't done very many autotunes, most of the motors that I use with drives are not pushed very hard. 

The ones that are operating near their limits I will autotune no matter what it takes.


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## micromind

frenchelectrican said:


> This is one of few most common way to destory the drive.
> 
> That why with the disconnect switch I always add a aux switch concants to prevent this mess.,,


Another quick easy way to wreck a drive is to megger the motor while it is still connected to the drive.


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## frenchelectrican

micromind said:


> Another quick easy way to wreck a drive is to megger the motor while it is still connected to the drive.


Heck ya that is the other common way to destory a good drive unit.,,


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## glen1971

Mike_kilroy said:


> Also please clarify for me: replacing a motor with a NEW motor of exactly the same part number, your drives require re-autotuning?


Lots of drives require this as part of their set-up... Several drives also have a setting to allow the load to stay connected...


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## Mike_kilroy

glen1971 said:


> Lots of drives require this as part of their set-up... Several drives also have a setting to allow the load to stay connected...


Lots?

Please share a single model, mfgr, and copy of instruction in manual, that requires re-autotuning if motor changed to an identical one. 

You will not be able to as the tuning is digital and what is correct for one motor is also correct for an identical replacement motor. there are no significant differences in any parameter between identical part number motors.


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## glen1971

Mike - You're right.. It's not listed in the manuals that I can think of... But can you guarantee that the last electrician, or the initial install, had it done? On most installations, I can't so for the few extra minutes it takes, I know it's done... 

I also can't guarantee that the replacement motor is the exact replacement for what was set-up on the drive... The hp, frame, volts, enclosure and speed would be, but that would be where most "exacts" end...

And if I'm changing one component I'll take the time and do it, then I know..


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## Mike_kilroy

All good reasons to do as you say Glen. That is not the world I live in. In my world the motors are very sophisticated and special, seldom general duty. So if I had a machine with a xyz2412abc motor, it will get EXACTLY the same motor model put back on.

And although I often say "I'm from Missouri, prove it," if the drive/motor ran correctly before the motor had to be replaced, then I see no reason to retune it. 

If it was a more general machine and someone replaced the motor with a different model, then of course all bets are off.


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## Jhellwig

I dunno what your world is but retuning after it is messed with just good practice. Stuff changes. No two motors are the same.


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## Mike_kilroy

Jhellwig said:


> I dunno what your world is but retuning after it is messed with just good practice. Stuff changes. No two motors are the same.


"No two motors are the same" is not true for same part number motors in your world too my friend.

Do you understand what autotuning calculates? Here is a typical list:

https://www.dropbox.com/s/6g6yyc3e0w2zfud/autotune.jpg?dl=0

Do you think when a motor manufacturer manufactures a motor they just randomly add turns with random size wire? Random squirrel cage lengths? 

https://www.dropbox.com/s/5t080o1w03c2dpf/motor spec.jpg?dl=0

Is a typical motor spec sheet. You can see that ALL the values autotune attempts to calculate are fully defined and have a spec. No random numbers here. 

So if you have done an autotune on a vfd with a given motor, and then you change that given motor with another with the same exact model, there is absolutely zero need to do an autotune again.

If you followed this far, you will see that velocity loop gains are also adjusted: these are due to the LOAD (inertia) on the motor. So again, unless you change the LOAD when you change the motor, there is no reason to autotune again. 

Now if you are paid by the hour, you may an ulterior motive to spend time autotuning, but we don't need to get into ethics.


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## Safari

(Its been a while since I made a post)
So I recently hooked up a Yaskawa drive 37 kw.and provided star delta capability if say the drive fails.

If say the drive was in running mode and the operator selects stardelta mode.The two output contactors from drive will open immediately. 

Will this also destroy the drive? 

Sent from my HUAWEI Y330-U01 using Tapatalk


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## Mike_kilroy

Depends on the Yaskaw model; if real old, yes, it likely would blow output transistors. if fairly new model, should not hurt it.

You will get the typical "OMG open output of running vfd will destroy it!" too...

Years ago, this was true, but IGBTs today have hefty built in reverse diodes across them that eliminate the large voltage spike that otherwise can happen. 

THAT said, should you do this? No, it is not good engineering practice. If you have some type of machine that REQUIRES an output contactor for some reason, then interlocking an auxiliary contact back to drive enable or run input to shut it off first is good idea.


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## Mike_kilroy

Safari said:


> (Its been a while since I made a post)


I love your avitar! Being in Kenya, I assume getting a replacement drive is rather difficult, so your concern seems very smart!!


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## Safari

Mike_kilroy said:


> Depends on the Yaskaw model; if real old, yes, it likely would blow output transistors. if fairly new model, should not hurt it.
> 
> You will get the typical "OMG open output of running vfd will destroy it!" too...
> 
> Years ago, this was true, but IGBTs today have hefty built in reverse diodes across them that eliminate the large voltage spike that otherwise can happen.
> 
> THAT said, should you do this? No, it is not good engineering practice. If you have some type of machine that REQUIRES an output contactor for some reason, then interlocking an auxiliary contact back to drive enable or run input to shut it off first is good idea.


Thanks mike_kilroy ,sorry I didn't realize I repeated myself "if say"
.......
I need to check how old it is ,am not in the plant until Wednesday, but yes I did use the output relay of the drive to provide running feedback to the plc since the selection drive and star delta is through plc program.
Even with this in place ,in running state I can select either and output contactors of the mode running(drive or stardelta will disengage. I should introduce timer block .

Sent from my HUAWEI Y330-U01 using Tapatalk


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## Safari

Mike_kilroy said:


> I love your avitar! Being in Kenya, I assume getting a replacement drive is rather difficult, so your concern seems very smart!!


It is difficult yes,mostly we buy from dealers in India.

Sent from my HUAWEI Y330-U01 using Tapatalk


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## Safari

Mike_kilroy said:


> I love your avitar! Being in Kenya, I assume getting a replacement drive is rather difficult, so your concern seems very smart!!


Thanks..the avatar has some humour in it.There is a tribe in kenya ,i
t is said they love the Radio stereo so much that even when it floods its the ONLY thing that they value and will save from the house.[emoji2] 

Sent from my HUAWEI Y330-U01 using Tapatalk


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## Jhellwig

Mike_kilroy said:


> "No two motors are the same" is not true for same part number motors in your world too my friend.
> 
> Do you understand what autotuning calculates? Here is a typical list:
> 
> https://www.dropbox.com/s/6g6yyc3e0w2zfud/autotune.jpg?dl=0
> 
> Do you think when a motor manufacturer manufactures a motor they just randomly add turns with random size wire? Random squirrel cage lengths?
> 
> https://www.dropbox.com/s/5t080o1w03c2dpf/motor spec.jpg?dl=0
> 
> Is a typical motor spec sheet. You can see that ALL the values autotune attempts to calculate are fully defined and have a spec. No random numbers here.
> 
> So if you have done an autotune on a vfd with a given motor, and then you change that given motor with another with the same exact model, there is absolutely zero need to do an autotune again.
> 
> If you followed this far, you will see that velocity loop gains are also adjusted: these are due to the LOAD (inertia) on the motor. So again, unless you change the LOAD when you change the motor, there is no reason to autotune again.
> 
> Now if you are paid by the hour, you may an ulterior motive to spend time autotuning, but we don't need to get into ethics.


You need to back off a bit. I have changed enough motors and drives to know what I am talking about.If you have ever seen a motor analysis you would know that not two are the same. That is why the send a test sheet with every one. There can also be revision changes on a model of motor or change in manufacturing practices that affect the motor not to mention that storage has a huge effect on it. Then you have the variables in the wiring and installation and deterioration of the drive components.


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## glen1971

Mike_kilroy said:


> Now if you are paid by the hour, you may an ulterior motive to spend time autotuning, but we don't need to get into ethics.


Umm... How long does your Autotune take? 10 minutes-ish? 20? How much productivity is lost due to people staring at smart phones checking who's dog crapped on what lawn or what the latest ET posts are? If you want to discuss ethics....


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## Mike_kilroy

Jhellwig said:


> You need to back off a bit. I have changed enough motors and drives to know what I am talking about.


Back off? Whew. OK, will do sir. Funny, I gave the solution to the OP while you guys spewed how to megger the motor, but ok.

Just for reference, after 41 years as design engineer of drives, firmware analysis and correction thereof of drives, motor application sizing software, applying motors to machinery, guess I have no clue. Funny that folks pay me $ 2500/day for consultation to diagnose and identify and then fix their drive problems after many others have tried and failed (and I have in each case solved them). But guess I have no clue.

I will just end with saying you are wrong about the need to autotune so much. There are tolerances on each motor specification and as long as a motor model meets the tolerances, it will behave on a drive just like all the others of the same part number. For some reason you erroneously believe a 5 or 10% change in a vector variable will make a significant difference. Keep believing it and autotuning.


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## Jhellwig

Mike_kilroy said:


> Back off? Whew. OK, will do sir. Funny, I gave the solution to the OP while you guys spewed how to megger the motor, but ok.
> 
> Just for reference, after 41 years as design engineer of drives, firmware analysis and correction thereof of drives, motor application sizing software, applying motors to machinery, guess I have no clue. Funny that folks pay me $ 2500/day for consultation to diagnose and identify and then fix their drive problems after many others have tried and failed (and I have in each case solved them). But guess I have no clue.
> 
> I will just end with saying you are wrong about the need to autotune so much. There are tolerances on each motor specification and as long as a motor model meets the tolerances, it will behave on a drive just like all the others of the same part number. For some reason you erroneously believe a 5 or 10% change in a vector variable will make a significant difference. Keep believing it and autotuning.


Talking down to people isn't going to get you anywhere around here. First you insinuated that people getting paid by the hour are just wasting time playing around so you are already very low on everyone list. Now you are proclaiming how much you get paid to solve what in your world are minor issues isnt going to impress anyone and just makes you look like a douche. 

Yeah, drives are hard to figure out. Some people are good at them and some aren't. You happen to be talking to several people that are good with them. I suggest you prove your knowledge instead of proclaiming it. Or just leave. No one here is fond of engineers anyways.

Ps. Since you know everything you know that static tune on ab drives takes less than a minute to do so there isn't much time wasted.


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## micromind

glen1971 said:


> Umm... How long does your Autotune take? 10 minutes-ish? 20? How much productivity is lost due to people staring at smart phones checking who's dog crapped on what lawn or what the latest ET posts are? If you want to discuss ethics....


If you need to de-couple the motor from the load, it can take hours........lol.


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## Safari

Am following......

Sent from my HUAWEI Y330-U01 using Tapatalk


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## JRaef

Not all VFDs have an option for a Static tune, true. But the PF525 does, and it's fine for 99% of applications. Takes a minute of so at initial setup, no need to disconnect the load.

Do you need to do an Auto-tune every time you change a motor with the EXACT same motor? No.

Have I EVER seen someone replace a motor with the EXACT same motor? Once, in 30+ years in the business. I've never worked for a precision machinery OEM however, so maybe that's why. In the field, you put in what you get fast, because when production is down and the plant manager is screaming at you about why the machine is not running, and you say "I'm waiting for the motor to be shipped because I need the EXACT same motor to avoid doing an Autotune in the VFD...", your resume had better be up to date.


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## stuiec

JRaef said:


> Not all VFDs have an option for a Static tune, true. But the PF525 does, and it's fine for 99% of applications. Takes a minute of so at initial setup, no need to disconnect the load.
> 
> Do you need to do an Auto-tune every time you change a motor with the EXACT same motor? No.
> 
> Have I EVER seen someone replace a motor with the EXACT same motor? Once, in 30+ years in the business. I've never worked for a precision machinery OEM however, so maybe that's why. In the field, you put in what you get fast, because when production is down and the plant manager is screaming at you about why the machine is not running, and you say "I'm waiting for the motor to be shipped because I need the EXACT same motor to avoid doing an Autotune in the VFD...", your resume had better be up to date.


I have a similar situation to the OP, drive throws fault code 13. I have meggered everything downstream of the drive, everything looks good. This problem came up about a month ago. They swapped out the motor and the problem went away. After about 20hrs run time the problem is back with the new motor. 

What is the procedure for running autotune? P040 was set to Idle, I can change it to static......then what?


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## varmit

Referring back to the original post, did you verify that the power system is a wye and not a corner grounded delta, high leg system or ungrounded delta? If the power system is anything other than a wye system, the MOV jumper(s) MUST be removed. 

I have seen the MOV jumpers left in on non wye systems take out an AB VFD on initial power up. I have also seen some that lasted several years with the jumpers in while in use on a non wye system.


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## stuiec

varmit said:


> Referring back to the original post, did you verify that the power system is a wye and not a corner grounded delta, high leg system or ungrounded delta? If the power system is anything other than a wye system, the MOV jumper(s) MUST be removed.
> 
> I have seen the MOV jumpers left in on non wye systems take out an AB VFD on initial power up. I have also seen some that lasted several years with the jumpers in while in use on a non wye system.


not sure if you're talking to me....system here is a wye. There are numerous other identical drives at this site with no problems. I suspect that there is the chance that someone that had no business in the MCC was fooling around with this drive----other than myself that is :shifty:


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## varmit

stuiec said:


> not sure if you're talking to me....system here is a wye. There are numerous other identical drives at this site with no problems. I suspect that there is the chance that someone that had no business in the MCC was fooling around with this drive----other than myself that is :shifty:


Just thought that I would add that bit of info. I have seen this happen several times to folks.

It is impossible to know the real history of things that a person is trying to fix. Then there are the random premature failures that make maintenance so challenging.


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## JRaef

Something which might be related to this subject that I just learned in a class on avoiding problems with drive installations and is apparently something that happens more than I would have thought. 

In drive instruction manuals, they will tell you to ALWAYS terminate the motor ground wire to the DRIVE ground terminal, don't terminate the motor ground to the panel ground or ground bus and the panel ground to the drive. Terminate the motor ground to the drive, then terminate the drive to the enclosure, ground bus etc. Many drives provide you with two ground connection points for this reason. The reason they gave? Even if it works at first, over time there are plenty of places in that indirect ground connection that can build up corrosion and resistance, which then interrupts the flow of common mode noise current that is created by the drive, trying to get back to it, because common mode noise current is always trying to get back to its source. So when it can't, that means that some of the current leaving the drive is not getting back to it. If the amount of ground path resistance keeps increasing so that non-returning current value increases, that's often going to get picked up in the drives ground fault sensing. Worth checking into, it's a cheap fix.


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## geoffpowell

If you have or download the manual 520-UM001I-EN-E you will see it describes the basic procedure. You set P40 to 1 or 2 depending on whether you are doing a static or rotary auto tune. The parameter will reset to 0 when you are done. 

See http://ab.rockwellautomation.com/Drives/PowerFlex-525#documentation


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## stuiec

JRaef said:


> Something which might be related to this subject that I just learned in a class on avoiding problems with drive installations and is apparently something that happens more than I would have thought.
> 
> In drive instruction manuals, they will tell you to ALWAYS terminate the motor ground wire to the DRIVE ground terminal, don't terminate the motor ground to the panel ground or ground bus and the panel ground to the drive. Terminate the motor ground to the drive, then terminate the drive to the enclosure, ground bus etc. Many drives provide you with two ground connection points for this reason. The reason they gave? Even if it works at first, over time there are plenty of places in that indirect ground connection that can build up corrosion and resistance, which then interrupts the flow of common mode noise current that is created by the drive, trying to get back to it, because common mode noise current is always trying to get back to its source. So when it can't, that means that some of the current leaving the drive is not getting back to it. If the amount of ground path resistance keeps increasing so that non-returning current value increases, that's often going to get picked up in the drives ground fault sensing. Worth checking into, it's a cheap fix.


The motor ground is good. However the design here is 6 stainless tanks all connected with stainless process piping, all bonded together, with each tank having a motor bolted directly to a steel plate on the tank. All motors are on VFDs. Could it be the other drives' noise? This is the only drive kicking out fault codes so far. I don't know what else to look at...over 1000 Mohms each winding to gnd, same with the cabling.


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## Gates

JRaef said:


> Not all VFDs have an option for a Static tune, true. But the PF525 does, and it's fine for 99% of applications. Takes a minute of so at initial setup, no need to disconnect the load.
> 
> Do you need to do an Auto-tune every time you change a motor with the EXACT same motor? No.
> 
> Have I EVER seen someone replace a motor with the EXACT same motor? Once, in 30+ years in the business. I've never worked for a precision machinery OEM however, so maybe that's why. In the field, you put in what you get fast, because when production is down and the plant manager is screaming at you about why the machine is not running, and you say "I'm waiting for the motor to be shipped because I need the EXACT same motor to avoid doing an Autotune in the VFD...", your resume had better be up to date.


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## Gates

Excellent advice...love it.


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