Welcome to the forum clcarter50,
Assuming you have both hands in a cast and therefore cannot easilly use your keyboard to go to their website and download the manual, here it is, and your answer is on page 42. Would you like me to read it or you too?
All sarcasm aside, we love to help but please read the FAQs for this forum, particularly the part about doing basic things like Google searches on your own before asking for help. This was your only freebie just because I see that this is your first post, so enjoy it. After this, it'll cost ya!
"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more."
Nikola Tesla
Thank jraef
I went throught that, but its a little bit more than that I understand OSF is an over voltage fault, and this is on an gappex with 8 small belt and its only doing it on the #7 belt and when it happen it shut down the sorter.
Never worked with an Altivar before but, on some other drives an Overvoltage Fault can be caused by the load driving the motor. This happens particularly during Decel.
You might want to check the decel parameter in the drive. Compare it to the other drives. It might be too short, try stretching it out some.
Thank Ed
I am still working with it, I connected a recorder to it and recored it this is a 3 wire 3 phase I recorded max peak and Vab 746, Vbc 756, Vca 1.34 what could you make of this.
You must be connecting your recorder to the output of the VFD, and what it will be able to read there will be pretty much useless as a diagnostic tool. That said, it is interesting that a-c phase is only showing 1.34V, but that could just be a quirk of your recorder not being able to interpret a PWM output signal properly. If that voltage were true, you would be getting an output phase loss trip instead of an over voltage trip.
As fangas (Ed) mentioned above, the most common cause of an overvoltage trip on a VFD is from an overhauling load, meaning the load is trying to make the motor go faster than the VFD is telling it to. This turns the motor into an induction generator and puts voltage back into the VFD. If the VFD is not fitted with braking resistors to dissipate this excess enegy as heat, it protects itself by tripping off line. On your drive however, there is a separate fault code for that instance (ObF). I find that interesting because I am curious as to how the Altivar could tell the difference. If we assume they can it leaves only a few other possibilities;
1) You are getting "cross talk" from the other VFDs on the same system in the form of harmonic voltages that for some reason are manifesting themselves onto that VFD. Putting line reactors in the VFD circuit would clarify that in 99% of the cases.
2) As you shed loads on your sorter, your voltage is increasing because you had been overloading a transformer somewhere upstream, and someone fixed that problem by changing the transformer taps to overcome the voltage drop. As you shed loads and remove the cause of that one problem, you now have a new one. The problem with that theory is that #8 should then have that problem too, and you didn't mention that.
3) Someone has put in either Power Factor Correction (PFC) capacitors upstream of the VFDs, or has installed a harmonic filter that has tuned capacitors in it, and again, as you shed loads there is a resonnance that developes and manifests itself in that 7th VFD by building up a charge on it's DC bus. I see this happen sometimes in areas where the utility uses capacitors to help balance or boost their line voltages (although they never admit it), but in those cases it affects all VFDs on the site. If it is affecting only this one VFD, the caps would be much more local to this system. Check your entire system carefully for capacitors, then try to determine why they are there. If they were for PFC, they may not be necessary as the VFDs will present a decent PF to the line already. If they are in harmonic filters, it nay be necessary to turn all of the VFDs off at once to avoid this, or just live with it. A line reactor on this drive may help out if you choose to live with it.
Good luck (and I appologize for appearing harsh in my first post).
"Our virtues and our failings are inseparable, like force and matter. When they separate, man is no more."
Nikola Tesla
Hold it guys. The poster said he had a 3 wire 3 phase power system. That, to me, means a floating delta transformer secondary with no neutral. If he is reading voltage from phase to ground and one leg is grounded, there you have it.
On many drives built with a CE label, the internals of the drive include a noise-suppression network which is designed with a balanced source in mind. When the input is unbalanced, this network can pump up the DC bus and cause a fault. I have seen the fault appear immediately on startup or, depending on the amount of imbalance, it may be intermittent or occur only when running.
Usually, the drive manufacturer provides a way to disconnect the internal network and then the drive operates normally.
I'd check for this first. It sounds familiar to me.
DickDV,
Interesting point, I'd like to know more about that for future reference. But if that were the case here, wouldn't it be the same for all 8 drives and not just #7? I suppose that the same issues of load shedding could apply to this phemomenon however. Worth checking in to.
Sorry to be so late in this interesting discussion. But the benefit of being late is that you may see things clearer than just after the Big Bang with all the dust whirling around. And what I see is that we really do not know much about your installation.
1 What IS your feeding system? Is a floating one (IT) or one with a grounded neutral (TN)?
2 What is your system voltage? Is it around 500 V phase-phase? Or something else?
3 Is it at all possible that the load regenerates (feeding energy back to the inverters)? Either in operation or during deceleration?
4 Does your inverters have braking resistors?
5 When recording motor voltage on a PWM inverter, you will not record the fundamental but the sum of all PWM components. These components usually add up to a rather high value - often close to the Udc voltage. So this voltage doesn't say anything about the voltage producing torque in the motor. You need a filter to keep PWM components away from the recorder. Is there such a filter? A filter having 200 - 500 Hz corner frequency is OK if the motor frequency is 0 - 50 Hz and the switching frequency is 4+ kHz.
6 Are you sure that the recorder works on all channels? Try and shift chanels to see what result you get.
7 I would go with DickDV (floating supply and ground fault on one phase) if you hadn't told us that you measured Vab 746, Vbc 756, Vca 1.34 which clearly says that you measured main voltages and not phase-ground voltages.
Just to add another point. The Altivar 18 differentiates between an overvoltage during braking (it will bring up the trip code ObF) and an overvoltage during steady state and acceleration, the latter being OSF. So, with this information, I would be concentrating on the other points raised already other than overvoltage due to regeneration during stopping. It could be regeneration due to an overhauling load but we need to come back to clcarter50 to find out more about the application.
If it is related to being connected to an IT network, I think I'm right in saying the ATV 18 had an integral EMC filter up to 15kW so this would cause a number of issues relating to instability.
Thank Guys, I ran this gappex on Fri. and it ran fine in the normal mode never once did I put it in the bypass mode which make me believe that you may be right DickDV this problem could be intermittance. Out of 8 VFDs #7 the only one stopping the Sorter. we change out the VFD and the #7 motor also.
OK. You say that you record maximum voltage (3 wire 3 phase I recorded max peak and Vab 746, Vbc 756, Vca 1.34). If the "max peak" function is a fast one then you have probably recorded some kind of a transient - and they usually mean nothing (overvoltage function always filtered or delayed to avoid nuisance tripping).
This has been an interesting field day, but I think that you should do some more work on your own. Coming here asking "I have an overvoltage trip. What's the problem?" is not a very efficient way of doing it. It creates a lot of confusion and guesswork.
And, please, make sure that you know what you measure, in what units and also what properties your instruments have. There is a big difference between AVG, RMS, PK and "MAX PK". Also, the bandwidth of the instrument counts.
I quote jraef: "Good luck (and I appologize for appearing harsh in my first post)" But substitute last for first.
![[bigcheeks]](/data/assets/smilies/bigcheeks.gif "[bigcheeks] [bigcheeks]")