VFD Blown

[CanuckEngineer]

Hello All,

I am sorry I don't have all the technical details but I wanted to pick your brains for some initial options.

The engineer on one of my project has specified IPS VFD's drives to run pumps for a pool system (sorry, right now don't know which pumps, and what the exact HP is, however my guess is 600Volt, 3 phase, 10 to 15 HP).

The VFD's have blown just recently (fuses blown and internal circuitry totally fried).

IPC is blaming fluctuations on the incoming power supply.

Coordination study has been done on the site however vfd is still toast.

Assuming that the hydro supply is sufficient can you guys recommend some issues on what could cause the VFD issues, local to the VFD?

p.s. I will post more technical data as I get it next week.

Much thanks,

RK.

 

[itsmoked]

Lightning is always a favorite followed by other various PoCo debacles and upsets. Did any other electrical gear also die at the same time? You generally need to build a case. Having two of the same devices die at the same time is building a pretty good case. Now you just need another device hopefully on a different circuit to have toasted too.

Bsck to the VFDs. We do need more to go on. Did they both really fail at the same time or is this some serial event?

Keith Cress
kcress -

http://www.flaminsystems.com

 

[CanuckEngineer]

Thanks Keith.

Good points.

The building is just in the hand-over stage, so basically it is still 'pretty-fresh and new'.

I know the electrician has been complaining about power issues for a couple of months now but to my knowledge I am not aware of any other equipment failure or any power quality studies done to date.

I will raise the questions next week and try to get more info.

Regards,

RK.

 

[Skogsgurra]

With pumps and VFDs, there's always a risk that the liquid drives the pump during fast ramp-down or a plain switch-off.

If there are two pumps working in parallel, you can also have an idling pump running backwards, driven by pressure from the running pump.

If there is no regen or braking (brake resistor), the DC link gets pumped up and that results in an overvoltage with the consequences you describe. I do not think that it is about power quality. It almost never is.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[CanuckEngineer]

Thanks Skogsgurra.

Very good info.

I will relay some of these points next week in the meetings.

Best Regards,

RK.

 

[jraef]

Is this the Flowserve IPS Temp drive? If so it appears to be a knock-off of the Rockwell PowerFlex 700 and if they copied it down to the details, it might be that you missed a step in the installation.

If you have an ungrounded delta power system, or a resistance grounded wye power system, there is a reference jumper to ground within the front-end of the drive that must be removed. Failure to do so kills the drive's surge arrestors on the first line spike, then they are no longer there so line spike #2 kills the front end of the drive. All drives are like this actually, it's just a simple process of removing a jumper on the PowerFlex drives but often times with copycat products, those little details, such as the instructions to remove it, get lost. If you have a solidly grounded wye power system, as in 600Y347, then this is not the issue.


"You measure the size of the accomplishment by the obstacles you had to overcome to reach your goals" -- Booker T. Washington

 

[X49]

I have experienced multiple drives on failing simultaneously in a new facility. They were small drives installed on a large 600V system without line reactors. It was presumed that they had failed due to line disturbances. They were the only two drives without line reactors, and the only two drives in the facility to fail. Line reactors were installed, as was recommended by the manufacturer's literature for drives installed on large systems (>500kVA), and as far as I know the problem did not resurface.

 

[mikekilroy]

So when you get more details, find out if the blown stuff is on the INPUT or the OUTPUT of the drive; different things cause each. I assume INPUT since you mentioned fuses also, although shorted outputs also should pop the input fuses. Where is this located? Do find out if Delta or Wye (and if X0 is grounded) power source for better feedback too.

Minus the additional info you are gathering, the only other generic thing worth mentioning since this is a new install, I have seen drives blow repeatedly from a loose phase somewhere upstream on the INPUT (that can cause those very high voltage spikes Jraef mentioned too).

http://www.KilroyWasHere<dot>com