PowerFlex 700 not powering up

Hey everyone,

Posting this for my boss who's onsite installing a replacement PowerFlex 700 after another one failed yesterday. Looks like one of the original IGBT modules fried on the original drive, and notably the common mode capacitor/MOV jumpers were NOT removed on the original drive, whereas every other drive I've ever worked on at this site (power plant) has required all common mode cap/MOV jumpers to be removed because of an ungrounded delta secondary system.

They removed the original drive and put in the new drive - refurbished by Rockwell - new drive has the same catalog number aside from the enclosure, original was NEMA 12, replacement is NEMA 1, which shouldn't be an issue because the originals were inside enclosures in a relatively clean/dry air conditioned room. When they got all the power and I/O connections moved over to the new drive, they turned the supply power on and the green "POWER" LED did not come on. They checked voltage on all 3 phases (600VAC) and measured ~600VAC phase to phase and 347VAC phase to ground on all three phases.

Short of an actual bad drive, is there anything else that could cause this? Connections knocked loose in shipping etc.? I would really hope that Rockwell would have tested that the drive powers up after refurbishment, but I've seen stranger (stupider) things.

Thanks!

EDIT: Should have added that they did remove the capacitor/MOV jumpers on the new drive, and the original drive was only in service for just over 5 years (installed in July 2017).

I'm not familiar with that exact model PowerFlex drive, but...is the 24V control power supply to it present? Some drives need that external connection, but I suspect the drive is DOA.



I'd contact Rockwell or your local distributor who sold you the refurbished drive for support. Tell them it was DOA and get an expedited replacement.

My boss said there's no voltage on the DC bus, so either the SCR control board or the SCRs themselves seem to be toast; in short, the drive does seem to be DOA. Got that info after work yesterday so I didn't get to post an update.

Is it a model that will power up the controls with 24v applied to the auxilliary terminals? Manual says this can only be done if the 15th position of the catalog number is C or D and to not try it if it's A, B or N.
Other than that the manual has several references to the drive not starting if several conditions with jumpers and digital inputs aren't met, but I can't see it failing to power up because of this.

Puddle said:

Is it a model that will power up the controls with 24v applied to the auxilliary terminals? Manual says this can only be done if the 15th position of the catalog number is C or D and to not try it if it's A, B or N.
Other than that the manual has several references to the drive not starting if several conditions with jumpers and digital inputs aren't met, but I can't see it failing to power up because of this.

Click to expand...

The drive has the 115VAC Vector I/O module (D), but I believe it's a frame size 5, so I don't believe the auxiliary control power terminals are present unfortunately (only available on frames 7-10).

Hey everyone, got this figured out. It turns out that the electricians didn't actually take phase-to-phase readings (to reiterate, I wasn't onsite and was posting this on behalf of my boss), and instead only took phase-to-ground readings. There actually was no voltage on A phase, but they were reading 347V to ground back through the primary of the control transformer, or at least I'm pretty sure that's what was occurring. There was actually a current limiting fuse block stuck into the bottom of the supply breaker and the fuse on the A phase had blown, so that explains the lack of voltage there. The customer had ordered a second replacement drive and when they put it in and applied power, the same thing occurred as the first replacement drive. I guess on the plus side they now have another spare for the system at least.

Thank you for the followup! And, yeah, it's annoying when someone says,"I checked it!!" I've learned (the hard way...) to always ask them, "How did you check it?"


I have on my desk an aluminum coupling that drove a DC tach generator from the gearbox of a rolling mill that the electricians insisted they checked. The setscrews had come loose and it was rubbing on the generator housing so long/hard that it melted a blob of aluminum off itself. I spent *hours* trying to figure out why the drives that used that tach signal as their speed reference were so erratic...sigh...