ingersoll rand VFD critical fault - solution

[living2learn]

I have an ingersoll rand 75hp, 480V air compressor. The utility that serves my site constanly has voltage drops that engage the critical fault 16 in my vfd. The problem with the critical fault is it requires a human to manually reset the system to restart, but a typical power outage does not require human interaction. The critical fault 16 is a DC undervoltage on the VFD. The ingersoll rand warranty is irrelevant, because this shutdown costs more than the compressor.

Porposed solution. Intercept the critical fault and route it to a relay that disconnects power to the unit - thus protecting it from a voltage sag. The relay will engage a 200A, 480V contactor that will isolate the compressor. Once power has been restored and my voltage sensing relay installed next to the contactor engages it will provide power to my air compressor.

Could I use a motor starter as the contactor?
What about a 200A lighting contactor?
Has anybody worked on these ingersoll rand compressors?

Thanks in advance for your input.

 

[jraef]

The type of contactor is irrelevant. Having a contactor ahead of the VFD is OK if it is only for emergency operations, but regular repeated cycling on and off can shorten the useful life of the VFD by stressing the capacitors and/or pre-charge resistor (if any). You might be better served by checking with IR for additional options with regards to automatic resetting of that fault.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[itsmoked]

These drop-outs occur while the compressor is running? You could detect the disturbance and have the compressor just shut down. Using a contactor to disconnect it seems like a sledgehammer solution.

Keith Cress
kcress -

http://www.flaminsystems.com

 

[Skogsgurra]

If IR doesn't have a simple solution like changing the limit for DC link, delaying the shut-off or activating the automatic re-start option, then it will be a better solution to simply change the VFD make to have those possibilities instead of keeping a unit that doesn't have them.

But, if the VFD is of later years - even ten years old - then those options should be availabe. It is often a question of finding the right parameter and setting it correctly. Your local rep should be able to do it if he is any good.

Letting a contactor or breaker disconnect is usually not such a good idea because the time to detect a dip plus reaction time and drop out time of the contactor/breaker usually is more than 30 - 40 milliseconds while most DC link supervisions react in less than a mains cycle (16.7 ms in the US and 20 ms in other parts of the world).

Gunnar Englund

http://www.gke.org

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

 

[jraef]

As I discovered and posted in the other forum, it appears this is a brand labeled Danfoss drive (osmosis, are you there?) and I believe there should be features that allow you to program the response to UV trips so that you can avoid the downtime. But rather than second guess why IR programmed it this way, you should elicit their involvement in this.

"Dear future generations: Please accept our apologies. We were rolling drunk on petroleum."
— Kilgore Trout (via Kurt Vonnegut)
For the best use of Eng-Tips, please click here -> faq731-376

 

[MiketheEngineer]

Probably expensive - but what about an UPS back up??

 

[Skogsgurra]

Not an option at all. For lots of reasons.

Gunnar Englund

http://www.gke.org

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

 

[ozmosis]

living2learn
is the VFD the TR200 from Trane? If so, then Alarm 16 is not undervoltage (Alarm 16 is short circuit). Undervoltage is Alarm 8.
If it is the TR200, then there are numerous facilities to overcome the problem described.
TR200 details:

http://www.trane.com/CPS/Uploads/UserFiles/Controls/VFD/BAS-SVX19A-EN.pdf

If not this drive, I suggest you advise which one then a more detailed reply can be proposed.

 

[gattie]

My experience with VFDs has been with Utility supply having very short duration (microsecond) spikes causing the drive to shut down
on overvoltage.
The spikes were caused by the Utility switching in Capacitor Banks
during peak demand periods to hold up the system voltage.
We solved the problem by fitting properly designed chokes to the line side mains connection of the VFD to filter out the spikes.