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After one week of operation w/o problems started getting 'DC bus high 7xx VDC' errors (where 7xx is DC bus trip voltage) as soon as KM1 line contactor closes for an I-R Nirvana VFD. Anybody else ever run into this?

Recently installed a model IRN200H-2S, 200HP Ingersoll-Rand Nirvana air compressor.

It is fed from a PMT which also serves a process line equipped with various and sundry inverter and servo drives, but with a largish Eurotherm 590 DC drive (didn't look, but on the order of 500 HP) driving an extruder screw. All of the drives on the production line have suitably sized line reactors installed, including the EU590.
The Nirvana drive itself is equipped with an I-R part number 38036877 line reactor.

A Fluke Scopemeter shows extruder drive notching on the waveform at the Nirvana VFD line supply. The interesting thing is the notching gets *worse* as soon as the Nirvana air compressor VFD is brought across the bus. I'm told that (so long as it doesn't knee-cap itself with the high DC bus voltage error upon initial energization) the drive runs fine.

Today was my first intro to the problem, and I haven't talked to their tech support people, but I'm guessing the Nirvana VFD initializes at zero speed command, just happens to be regenerating back to the line at very nearly the same point on the AC cycle the extruder is notching, and is somehow messing with the Nirvana's DC trip detection.

Has anyone run into related problems with this particular unit (or I-R Nirvana VFD drives in general), and can shed some light on it?

My understanding is I-R pretty much wants to wash their hands of the situation (... "it's a plant power problem ..." ) so part two of the question is what remediation makes the most sense. Should I look into a high power active tracking filter?

I have faced a same type of problem but with Siemens drives, the solution at the end was the chock/input filters for both the drives.

We have been using 2 x 100HP Nirvana's since Jan 2005 and have experienced no problems what so ever. In fact we are already looking to install another 2 at the beginning of next year.

We have seen substantial savings in our electric bills which stacks up with what we were told when we bought the compressors. So really our experience has been all good so far.

I was told at the time we bought them that each and every compressor made at Ingersoll Rand is rigorously tested before being shipped so I wonder if the problems mentioned above have arisen due to being installed incorrectly or care not being taken during shipping.

I will keep an eye on our compressors and report back if I see any problems that may be of interest.

We've experienced multiple problems with a 100 hp Nirvana compressor. At one point, hall effect sensors on motor came loose, compressor down. Later, also experienced 'drive' problems. I-R tried the old "It must be your power" excuse. Techs couldn't find the problem, replaced drive, drive would still fault. Finally replaced motor, and problem went away. Speculate that a bad winding, possibly damaged by loose screw rattling around was the cause. Not being an EE, I can't offer any advice on your power issues. We've had nothing but problems with this compressor, and seriously doubt we'd even consider I-R in the future.

Wow - as a service manager for Ingersoll-Rand I am embarrassed! I don't know who you are using, but I have many resources available as well as well trained and experienced techs. Our territory is loaded with Nirvana's - some which are 5 years old. I would like to think that we have experienced and resolved every possible Nirvana problem. In fact, my confidence is so strong, I have pretty much purged my entire rental fleet of all fixed speed units and gone 100% to Nirvana's. If you want free technical advice mixed with experience and customer suport, do not hesitate to contact me at 513-459-4580 or jim_altonen@irco.com.

Regards, my apologies and a handshake,

Jim Altonen
Service and Rental Operations Manager
Ingersoll-Rand, Cincinnati, OH

Bob,

I am a service manager for Ingersoll-Rand in Cincinnati, OH. I would be very embarrassed if you were not provided with excellent tech support regardless of your location. If you would like, I have many resources and very experienced & well trained techs at my disposal. In fact, when I was in sales, I sold one of the very first trial units approximately 5 years ago. The unit was (and still is) flawless during the trial period which immediately increased our confidence level of the product when it was eventually released for production. Becasue of this, we have hundreds of Nirvana's in our territory. Since the product line is nearly 5 years old, we have also experienced pretty much every situation that could have occurred. My offer is that if you ever want tech support, please call (513-459-4580) or e-mail me (jim_altonen@irco.com). In return, I would like to find out if your problem is now resolved as well as what did you learn?

Regards and a handshake,

Jim Altonen

We encountered a similar problem and actually had a power quality study done. The independent power quality study proved that the issue was on the incoming power. SCRs tend to fire at the same point on an AC sine wave, so it is no surprise that your VFD had issues there. We have been told that an isolation transformer should eliminate the problem.

Hi...

I am planning for 100hp Nirvana. After reading all comments I am afraid to make a decision. I am more concerned about HPM efficiency. Can someone comment on this what drive are they using, what about harmonics emission level, is this EMC certified?

The drive is designed by Leroy-Somers, if memory serves, and we finally nailed what was happening.

Our Nirvana is fed from the far end of a bus located about 200' from the compressor, bus loads are primarily servo drives, a smattering of smaller AC and DC drives, and a 400HP DC drive, and it is fed from a lightly loaded fairly high impedence pad mount transformer. We have a 5% reactor in front of the Nirvana, but a line reactor doesn't do much until you get reasonable
levels of current flowing through it.

I hooked up a computer running an HMI program, and logged a bunch of Modbus registers every second... turns out I-R's auto-restart feature waits a while after the drive line contactor pulls in. Problem is, the big DC drive is notching the line fairly heavily, and the longer the wait, the higher the
Nirvana's DC bus voltage goes, and it trips on bus overvoltage before auto-restart can occur.

The drive runs fine if it is reset, and, immediately after the fault clears, and line contactor pulls it, it is manually started. Once the motor spins up and starts pulling load current, DC link voltages drop, and everything is
happy (as long as there is sufficient demand - if it reaches the high pressure setpoint, and the drive is shut down ...well, rinse and repeat).

I don't know the nature of it's certifications, but I think it is made in France, and everything else I see coming in from the EU has been good in
regard to emissions. Our local distributor did well by us for what they could learn, but my impression is I-R is a tad neurotic when it comes to discussing anything 'under the hood'... which, unfortunately, is where one needs to be to troubleshoot this type of problem. My suggestion was shot down, but it seems to me that a bit of hardware tweaking in the design (there is only one DC link reactor in the positive bus; maybe adding one on the negative bus as well would help) in conjunction with not waiting so long to do the auto-restart would get rid of the problem.

We haven't finished it yet, but are juggling around our loads in order to feed it from a different bus (lower Z transformer, only one big DC drive on it, and the remainder primarily inductive loads), and that should take care of the problem. An isolation transformer would probably work as well, but we don't have enough room to mount one.

Except for this, the Nirvana has performed well, and shouldn't be a problem unless you also have high horsepower 6 pulse SCR bridges on the bus you'll be using.