VFD Failure after VFD Failure after VFD Failure after VFD Failure

Saturn_Europa

Saturn_Europa

Senior Member
Location
Fishing Industry
Occupation
Electrician Limited License NC, QMED Electrician
I am helping a colleague at a different facility troubleshoot a problem with a Flottweg Decanter. Its a remote facility with its own power generation.

The drive specifics:

ACS880 -01-124A-5
3PH, 380-500V
124A
75KW/100HP
FRAME 6
VAR jumpers to Ground have been pulled.

Attached drawings do not show line reactor. But there's one installed.

The original drive failed during operation. The electrician onsite, megged out the motor, which passed. The drive is powered thru its own fuses, thru a contactor that is latched in by a safety relay, then thru a line reactor.

The UDC + and UDC- are connected to a Power Ohm breaking module (with an external resistor) and UDC + and UDC - are connected to a 684 DC to 24 DC converter to a redundancy module for the 24v control voltage (Ive only seen this set up in Flottweg panels).

He installed a spare VFD that he had onsite. It would not power up. He checked voltage at the input side of the drive. 485v AC phase to phase and 278, 280 and 286 phase to ground.

The onsite electrician, checks the line reactor and everything looks good. Does an electrical tightening of the cabinet. Checks out the contactor then gets out the other brand new spare VFD.

He hooks it up to temporary power, the VFD powers up and he programs it. Then he installs it in the cabinet and only hooks it up to incoming line power. No control wiring and the UDC not hook up to the power ohm or anything else. Drive does not power up. Checks voltage at terminals. Voltage is good.

He takes the drive out and installs it on temporary power. The drive will not power up. He checks the charging resistor on the VFD and it reads OL. He puts a scope on the power in the cabinet and everything is good. Pulls out smaller Leeson VFD for a different application he has and installs it in the cabinet. It powers up.


The electrician onsite then gets a spare from my facility. Its a very new spare and has not been in storage for long. He installs it with all control power, load and line and breaking resistor hooked up. It powers up. He programs it and gets everything buttoned up. When the power is cycled the drive is dead and will not work.

The decanter has burned thru 4 drives.

Power tests good.
Line reactor test good.
Fuses are good.
Contactor doesnt chatter and pulls in once.

I am not onsite.

The only thing I can think of is that the line reactor is bad and he cant id the problem with it with a multimeter and a megger and its frying the drives for some reason.

I think the next step is to replace the contactor, the fuses, and the line reactor.

Has anyone ever seen anything like this?
 

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synchro said:
Does the charging resistor measure as an open circuit on all of the drives that have failed?
Click to expand...
I don't think the onsite electrician has checked all the failed drives. But I can ask him to check.

Looking back through some of Jraef's old comments it sounds like the power supply boards are going out. There's no bang, no smoke, no sparks. Just no LED lights and no display on the keypad and a non-functioning very expensive VFD.

I am going to ask the onsite electrician to take apart the contactor and see how the contact faces are. And also set up the scope on the input into the drive then cycle the contactor using the E-Stop and safety relay. Maybe there's a bunch of corrosion in the contactor causing it to single phase briefly during closure.

I am also going to ask him to physically remove the components in the cabinet and inspect them. Pull the fuses out. Unbolt the fuse holders. Take the Power Ohm module out and inspect it.

If he can't find the problem using a meter and a megger maybe there's a component that failed and can be found by visually inspecting it.
 
I forgot to mention that there is another ACS880 VFD in the same cabinet for a scroll motor that is still working. It’s on a separate contractor and does not have a line reactor. Its a smaller 15hp unit.
 
Jraef said:
Thanks for the update. So often we don’t know how things turn out.
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I actually had myself convinced that the line reactor was the culprit. But I found a post of yours from 2017 were you talked about never seeing a line reactor fail in 30 years "just to simple of a component, just iron and copper"

Ironically the post was about you troubleshooting line reactor failures that were catching fire on NON RUNNING drives.

Its a good read if anyone is interested:

Possible reasons for VFD line reactor failure?

This is a new one on me. Someone called wanting my help on figuring out why they have had 3 failures of Line Reactors ahead of some 40HP VFDs. 30 years in this industry and I have never once seen a line reactor fail. It's too stupid of a device; wire and iron. What could fail? So far no details...
www.eng-tips.com www.eng-tips.com
 
Saturn_Europa said:
I actually had myself convinced that the line reactor was the culprit. But I found a post of yours from 2017 were you talked about never seeing a line reactor fail in 30 years "just to simple of a component, just iron and copper"

Ironically the post was about you troubleshooting line reactor failures that were catching fire on NON RUNNING drives.

Its a good read if anyone is interested:

Possible reasons for VFD line reactor failure?

This is a new one on me. Someone called wanting my help on figuring out why they have had 3 failures of Line Reactors ahead of some 40HP VFDs. 30 years in this industry and I have never once seen a line reactor fail. It's too stupid of a device; wire and iron. What could fail? So far no details...
www.eng-tips.com www.eng-tips.com
Click to expand...
Yeah, I remember that. There’s one where I probably should have followed up. Turned out there were NOT just line reactors, they were passive harmonic filters, built from scratch by the integrator, then installed without isolation contactors, so they were always on line even when their associated VFDs were not running. That meant their caps (part of the filter) were always in the circuit and there was resonance issue that went undetected and caused the fire. The fire was so complete that it had destroyed most of the filter components other than the reactor cores, hence us all thinking they were just reactors. The same integrator kept rebuilding them on site with the same mistake, hence it failing multiple times. Had them install isolation contactors so that the filter for a non-running drive was off line, problem went away.
 
We had over 500;drives with most having line reactors. After ten years of opening up line reactor covers that often required a 10' step ladder and never came across a bad one or one with bad connections masked our Drive tech and he said he never had one go bad so while troubleshooting problem with VFD'S . These were the basic line reactors. We did have some new fancy think they called them active line reactors that had one or two contactors, capacitors that down the road would fail.We had maybe six different size spare line reactors in bench stock collecting dust for over 15 years and stopped removing line reactors in drives that we trashed.
 
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