# Rockwell Powerflex 425 dramatic failure



## Wireman415 (Aug 17, 2016)

Could it have been bad power? It was also full of dirt from a salt/sand plant. Combined with high humidity it became conductive?


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## MDShunk (Jan 7, 2007)

Looks pretty typical of most VFD's I've ever dealt with that have failed. Normally it's the caps, but it looks like your IGBT took the hit.

425? You sure? Looks more like a 40. They make 525's too, but they're pretty new-ish in the market.


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## just the cowboy (Sep 4, 2013)

You answered part of it yourself, SALT and moisture = boom.


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## oliquir (Jan 13, 2011)

typical vfd failure when connected directly to breaker


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## gpop (May 14, 2018)

oliquir said:


> typical vfd failure when connected directly to breaker



If a vfd trips the breaker then you are pushing your luck. A vfd only needs about 1 amp of power to get the main control board online to do a self test. 
If we have a vfd pop its fuses or trip a breaker we install a 1 amp temporary fuse block to see if it will power up. (normally after testing for a dead short caused by a welded mov or a collapsed diode bridge). 

Even if the drive comes up it may report something like precharge fault which means its fried. (dont hit reset on a fault you do not understand as it will go bang). 

Hopefully you have learnt why fuses on a vfd's is a valid recommendation.


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## JRaef (Mar 23, 2009)

That's a PowerFlex 40 or maybe a PF4, there is no "425". A short on the output side will typically take out the IGBTs. The first time it tripped the breaker, but the damage was already done. Re-energizing it just caused the failed devices to actually grenade, but really, that was kind of a foregone conclusion. Fuses would not have helped.


Crud + moisture can absolutely cause that to happen. In the old days, the PC board(s) would have shorted out and killed it long before the IGBTs were going to fail. Now the boards are all "conformally coated" to resist the effects of moisture so the boards last longer. But if you still have contamination getting in it eventually makes it into the power circuit and kills it.


Before putting a new drive into service, megger your output cables to make sure there wasn't a shorted lead or winding somewhere. You don't want to find out it wasn't the crud in the drive by smoking another one...


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## LuckyLuke (Jun 1, 2015)

JRaef said:


> Before putting a new drive into service, megger your output cables to make sure there wasn't a shorted lead or winding somewhere. You don't want to find out it wasn't the crud in the drive by smoking another one...


You speak the truth there, that mistake cost me a lot of money one day.


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## John Valdes (May 17, 2007)

Funny to see that drive in an aggregate plant.
All my old aggregate customers used Weg, ABB or Benshaw. Of course it was all in their heads.
I remember once replacing a drive on a Sunday at a quarry with the only drive I had on the shelf. Baldor.
They had me call Benshaw's after hours number and told me to get it in by Monday morning.
So they got up and running with a drive that would have been just fine, but swapped it the next day with Benshaw.
They ate the cost of the Baldor drive (they kept it for emergency) paid for a courier on Sunday and paid us to remove the Baldor drive and install the Benshaw.


Looking back at the electrical superintendent for this company, I conclude he and all the honchos in that company/business were total jerks about everything.
The electrical guy blamed me for one next day delivery that got there the next day.
It got there at 3:00 pm. 

Since he did not get his drive first thing that morning, he got pissed at me and called my boss to complain.
I wish I could run into him again someday. Just to tell him what I wanted to tell him many times. MoFo!


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## JRaef (Mar 23, 2009)

LOL, and Benshaw doesn't even make their drives, they are brand-labeled from LSIS (the new name for the Korean electronics firm that was LG, for Lucky Goldstar, just the sort of name you want on your electrical gear...). At one place I worked years ago, LG approached us with that same deal, saying we would have an "exclusive" on selling their drives and controls in the US. Then they immediately signed up with Benshaw and another company called Cerus (now Franklin), then later yet started marketing on their own too. Luckily we had dragged our feet and never signed the deal. I guess the word "exclusive" means something different in Korean...


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## MDShunk (Jan 7, 2007)

Benshaw's have sort of a cult following in the mining areas. 

As long as the drive has the I/O points and parameters you need for your application, I'm actually comfortable with any brand. It's all in what you get used to in terms of the speed at which you can get it wired in and the parameters changed to match your application. Sort of like Fords vs Chevy. 

My two all time favorites, in terms of robustness are the original TB Woods drives and the Seco AC drives; each no longer made in their original form. I've got some of them approaching 30 years of service. 

Some PowerFlex drives have a power-on counter that will rollover after 47 years. I've yet to see a PowerFlex make it to 15.


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## paulengr (Oct 8, 2017)

Powerflex says very plainly 100,000 hours in the book. That’s something like a 90% or maybe 99% survival rate.

Cutler Hammer claims...wait for it...500,000 hours MTBF. No drive is going to last almost 60 years and experience is that those ones last 10-15 years. But still MTBF means the 50% failure rate in ideal 68 degrees F, 40% humidity conditions. And it’s not realistic that half your drives fail. So real world failure is like everyone else, 10-15 years.

The only ones that exceed this are some railroad traction drives that claim 200,000+.


Sent from my iPhone using Tapatalk


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## LARMGUY (Aug 22, 2010)

just a suggestion...


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