# Powerflex 4



## eutecticalloy (Dec 12, 2010)

Had a power flex 4 blow its line side fuses today. When I replaced the fuses every led on the drive came on and wouldn't reset. I replaced the drive and it ran fine. Did the over drive kick the can? Or am I overlooking some basic programming selection?


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## MDShunk (Jan 7, 2007)

Pretty good chance the drive bit the dust. Allen Bradley VFD's are damn-near self diagnostic. If the motor data was setup right, it would have faulted out if you had a load side problem. In this case, it's a pretty fair bet that something happened internally inside the drive and blew the line side fuses. Particularly since every LED on the thing lit up when you re-energized it. That's not a fault condition. That's a drive that's thoroughly effed up.


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## varmit (Apr 19, 2009)

You were correct to replace this drive. Pflex 4s are just a basic "it works or it doesn't" type device. If it was blowing line side fuses, assuming they were sized correctly, without the drive tripping on overcurrent, the drive has died. There are no field replaceable parts on these and AB does not even repair "4s". I do like these drives in their HP range. They are really user friendly to set up.


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## John Valdes (May 17, 2007)

Can the diode bridge be replaced in these controls? They are cheap and can sometimes be purchased 3rd party. It sounds like the bridge fried.


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## JRaef (Mar 23, 2009)

John Valdes said:


> Can the diode bridge be replaced in these controls? They are cheap and can sometimes be purchased 3rd party. It sounds like the bridge fried.


It does sound like the bridge, but no, it can't be replaced. They have an IPM, the all-in-one power module that has the diode bridge, load transistors, braking transistor and gate circuits all potted into a single unit, about the size of a credit card and maybe 1/4 - 1/2" thick.

IPMs:








A replacement would likely cost as much as a new drive by the time you finished messing with it, even if it only cost $20 for the part. You have to get the old one desoldered, install the new one and hope that nothing else was damaged in the fault or in the repair process.


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## eutecticalloy (Dec 12, 2010)

MDShunk said:


> Pretty good chance the drive bit the dust. Allen Bradley VFD's are damn-near self diagnostic. If the motor data was setup right, it would have faulted out if you had a load side problem. In this case, it's a pretty fair bet that something happened internally inside the drive and blew the line side fuses. Particularly since every LED on the thing lit up when you re-energized it. That's not a fault condition. That's a drive that's thoroughly effed up.


Line side fuses were doubled because some mechanic didn't want to know why they were blowing.


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## albert (Mar 17, 2011)

My experiance with Power Flex 4 is they are for clean electrical systems and very light duty. If you have other drives or larger loads cycling, you may still experiance issues. Next time consider replacing it with at least a PF40. Even line reactors do not always help resolve the issue because the buss voltage of the drive can fluctuate to quickly when line voltage swells due to loads de-energizing.

Regards,

Albert in Oakville


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## mutabi (Jun 2, 2009)

Just to add my experience with Powerflex 4's. They are disposable. I have found that shorted wiring on the load side will kill the drive. Whereas, in similar instances with an ABB drive, the drive will protect itself. A cheap drive. Easy to setup. Useful in certain instances, but you get what you pay for. We use them a lot.


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## eutecticalloy (Dec 12, 2010)

albert said:


> My experiance with Power Flex 4 is they are for clean electrical systems and very light duty. If you have other drives or larger loads cycling, you may still experiance issues. Next time consider replacing it with at least a PF40.


aren't power flex 4 made by abb as well ?


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## JRaef (Mar 23, 2009)

eutecticalloy said:


> aren't power flex 4 made by abb as well ?


No. There is no connection between A-B and ABB other than the alphabet.

Allen Bradley doesn't actually manufacture the PF4s or PF40s either though, they are built in Asia under contract as almost all small inexpensive drives are. They are not available under any other brand name however, because Rockwell keeps proprietary control over software and firmware inside the drives, as well as the Operator Interface and Communications options.

That said, the PF4/40 is not the most robust product Rockwell sells, the intent of that product is to compete in the "low end" component drive market. In that world, drives are not built to be repaired, it's less expensive to just replace them. There are however a lot, I mean a LOT of people who think those drives are great, the PF4/40 is the largest selling drive in North America in their class. If it does everything you want it to do, you don't need more.


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## eutecticalloy (Dec 12, 2010)

JRaef said:


> No. There is no connection between A-B and ABB other than the alphabet.
> 
> Allen Bradley doesn't actually manufacture the PF4s or PF40s either though, they are built in Asia under contract as almost all small inexpensive drives are. They are not available under any other brand name however, because Rockwell keeps proprietary control over software and firmware inside the drives, as well as the Operator Interface and Communications options.
> 
> That said, the PF4/40 is not the most robust product Rockwell sells, the intent of that product is to compete in the "low end" component drive market. In that world, drives are not built to be repaired, it's less expensive to just replace them. There are however a lot, I mean a LOT of people who think those drives are great, the PF4/40 is the largest selling drive in North America in their class. If it does everything you want it to do, you don't need more.


Yeah, its seems that the ones who set up most control panels prefer them because they are so easy to replace. The functions of most of the drives at my plant are simply speed control, acc/dec and synchronization. There is no need for much more. 

So what are your favorite drives?

Correction: Some of our equipment like out oven from Holland (yes Dutch Oven) has siemens drives and a some European drives as well, but they never have any problems with either of those.


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## JRaef (Mar 23, 2009)

eutecticalloy said:


> Yeah, its seems that the ones who set up most control panels prefer them because they are so easy to replace. The functions of most of the drives at my plant are simply speed control, acc/dec and synchronization. There is no need for much more.
> 
> So what are your favorite drives?
> 
> Correction: Some of our equipment like out oven from Holland (yes Dutch Oven) has siemens drives and a some European drives as well, but they never have any problems with either of those.


LOL, "Dutch Oven". :laughing: Do you get hazard pay for working on it, or do they just provide a gas mask?:whistling2:

My preference on drives actually is more related to my preference in distributors for drives. I want a LOCAL distributor that knows their product, has it on the shelf if I need it (within reason) and has a readily available support structure so I don't have to get out of bed at 3AM to get to the airport and go help someone. That's why I've always recommended A-B when I can (unless I worked for a competitor). But in full disclosure, they hired me about 6 months ago, so I am decidedly biased now. But I realize not everyone likes A-B and I keep an open mind.

I personally like the new A-B PF750 class drives (753, 755), but then again I'm kind of a drive nerd so I need a lot of gizmo features to feed my addiction. ABB ACS-800 and -550 drives are nice, I've always liked ABB's user interface. Of the Asian drives, Yaskawa is probably the best, but nothing wrong with Toshiba and Mitsubishi either, it's just getting harder and harder to find a good distributor for them. I used to work for Siemens and when they paid me to like their drives, I did. But now I don't have to and I'm glad because although they are fine, I think they are a PITA to program. But their connection to PLCs is as good as A-B and world-wide, Siemens sells more PLCs that anyone, so that's why you see them a lot in European machines. Schneider drives to me are the worst in that aspect. They may be OK, but the programming is horribly complex even for a drive nerd.

As far as "shaft turner" drives, I actually like the PF4/40s, I also like the Teco drives in their various formats depending on capabilities needed. About the only one's I tell people to stay away from are AC Tech (Leeson), Delta (also sold by Automation Destruct as Durapulse) and LS/LG drives (also sold by various people like Benshaw and Cerus). AC Tech and Delta are as cheap as can be, the LS/LG thing for me is because they lied to me once about their drive being vector when it was not and it almost cost me my job, so I will never forgive them.


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## eutecticalloy (Dec 12, 2010)

JRaef said:


> LOL, "Dutch Oven". :laughing: Do you get hazard pay for working on it, or do they just provide a gas mask?:whistling2:
> 
> My preference on drives actually is more related to my preference in distributors for drives. I want a LOCAL distributor that knows their product, has it on the shelf if I need it (within reason) and has a readily available support structure so I don't have to get out of bed at 3AM to get to the airport and go help someone. That's why I've always recommended A-B when I can (unless I worked for a competitor). But in full disclosure, they hired me about 6 months ago, so I am decidedly biased now. But I realize not everyone likes A-B and I keep an open mind.
> 
> ...


What its your job title/description?


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## JRaef (Mar 23, 2009)

eutecticalloy said:


> What its your job title/description?


Packaged Control Product Specialist, i.e. I'm responsible for Low Voltage and Medium Voltage MCCs, VFDs, Soft Starters etc, anything engineered and packaged by the factory, but not the actual components themselves.


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## MDShunk (Jan 7, 2007)

JRaef said:


> Packaged Control Product Specialist, i.e. I'm responsible for Low Voltage and Medium Voltage MCCs, VFDs, Soft Starters etc, anything engineered and packaged by the factory, but not the actual components themselves.


Do you take 2am technical help phonecalls from lowly electricians such as myself? (hint that I'm begging your cell number :whistling2 Don't know if you've seen any of my videos, but I've installed about a gazillion dollars worth of A-B MCC lineups in the last couple years.


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## JRaef (Mar 23, 2009)

MDShunk said:


> Do you take 2am technical help phonecalls from lowly electricians such as myself? (hint that I'm begging your cell number :whistling2 Don't know if you've seen any of my videos, but I've installed about a gazillion dollars worth of A-B MCC lineups in the last couple years.


Sure, you can call me at 2AM. I won't answer it, but you can call me... 

But if you didn't know, there is a 24/7/365 tech support number.
440-646-3434
You give them your phone number and they roust someone out of bed to call you back within an hour. Won't be me though, they don't pay ne enough!


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## GEORGE D (Apr 2, 2009)

Question for you drive experts, most likely a dumb one. Obviously I'm no vfd specialist and seldom deal with them but wanted to know if there is a way to troubleshoot one besides bypassing it? I had one once that was showing fault so I first removed load leads and fault went away. Then megged motor which checked fine. Vfd was the problem.


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## MDShunk (Jan 7, 2007)

GEORGE D said:


> Question for you drive experts, most likely a dumb one. Obviously I'm no vfd specialist and seldom deal with them but wanted to know if there is a way to troubleshoot one besides bypassing it? I had one once that was showing fault so I first removed load leads and fault went away. Then megged motor which checked fine. Vfd was the problem.


What was the fault??? Look it up. Might have nothing to do with ground faults. Running a vfd without a load is always a bad move. You can make scrap out of a perfectly good drive.


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## JRaef (Mar 23, 2009)

GEORGE D said:


> Question for you drive experts, most likely a dumb one. Obviously I'm no vfd specialist and seldom deal with them but wanted to know if there is a way to troubleshoot one besides bypassing it? I had one once that was showing fault so I first removed load leads and fault went away. Then megged motor which checked fine. Vfd was the problem.


There are no dumb questions except for those unasked.

But there is no simple answer to this one. VFD faults can come from so many different things, it's hard to guess at what that might have been long after the fact like this. Best guess I could make would be that the electronics in the VFD were sensing something else in the motor that you were not picking on on with the megger. Maybe condensation moisture that was in the windings when the drive tried to turn on and by the time it sat around until you meggered it, it had dried out? That happens quite a bit really. The motor protection capabilities of most VFDs far exceed what you are used to seeing with just plain overload relays. VFDs do a lot of predictive monitoring in order to help protect the VFD investment, which ends up catching problems that you may not have seen before until something smoked.

Generally I always suggest reading the VFD fault display / code and following the VFD instruction manual on what to check. If you have VFDs in a facility and don't know where the manuals are, it's pretty easy now to download manuals off of the internet, so a good practice is to make a list of your installed drives and get the manuals BEFORE you are in a rush to get it back on-line.

Not all VFDs are created equal however, especially when it comes to manuals, so I'm not foolish enough to suggwest that's the end-all / be-all solution, but it's a place to start. Just remember that 99% of problems are the ones that are easily diagnosed, don't let your imagination run away with you and start by assuming yours is the 1%.


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## GEORGE D (Apr 2, 2009)

MD, it's been a while since then, I think the fault wasn't a recognized one, no code in other words. Something was screwy about it if I remember correctly. Great info on not running one without load because I was unfortunately taught differently. So.... how would you check one in those circumstances?


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## MDShunk (Jan 7, 2007)

JRaef said:


> ...Generally I always suggest reading the VFD fault display / code and following the VFD instruction manual on what to check. If you have VFDs in a facility and don't know where the manuals are, it's pretty easy now to download manuals off of the internet, so a good practice is to make a list of your installed drives and get the manuals BEFORE you are in a rush to get it back on-line. ...


TIP: I print out the fault code page or pages on Avery 8-1/2 x 11 sticker paper and stick that label on the inside of the panel door (if installed in panel).


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## MDShunk (Jan 7, 2007)

JRaef said:


> ...Generally I always suggest reading the VFD fault display / code and following the VFD instruction manual on what to check. If you have VFDs in a facility and don't know where the manuals are, it's pretty easy now to download manuals off of the internet, so a good practice is to make a list of your installed drives and get the manuals BEFORE you are in a rush to get it back on-line. ...


TIP: I print out the fault code page or pages on Avery 8-1/2 x 11 sticker paper and stick that label on the inside of the panel door (if installed in panel).


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## MDShunk (Jan 7, 2007)

Another TIP: If you're using Allen Bradley drives, Drive Executive, RSLogix, or Drive Tools or whatever you use will let you print out all the drives parameters on a sheet of paper. Damned handy if you're faced with a totally dead drive and no HIM feature (or parameters never written to the HIM). Really speeds things up if you're not programming from scratch, struggling to get IP addresses and accel decels, motor data, and everything else that might have been changed among the 40-bajillion parameters.


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## bgleason (Mar 3, 2012)

I would definitely suspect that the drive crapped out.


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## bgleason (Mar 3, 2012)

When I worked in a pasta plant in Lees Summit, MO, we found a guy who repaired electronics boards and we actually had had him repair an old 1336 drive that had fried a few years back. The guy did a phenomenal job and was actually quite a bit cheaper then shipping it to Rockwell to have them repair it. We used this guy initially on an old PLC board that we had in one of our panels. He does AWESOME work.


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## bgleason (Mar 3, 2012)

Good point on printing out parameters MDShunk. I have been on both sides of that and life is a lot easier when you have record of those parameters.


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