IGBT Over Temperature Problem

Use one of these.

Check the power quality of supply into the VFD, might have some issue on quality, could be caused by voltage dropped (line side), probably, if not, it might be a load side issue as noted by previous commenters which I think, is most probable also. Look for irregularities of the dynamics of the crusher. (Angular speed & Load aspect)

Jraef is expert on this. Just hope that the guy could drop by and help you a bit.

The IGBTs are likely to be the weakest link in the chain. Be glad they are warning of overload before failing.

Is this a new set or a new problem on a known OK plant?

Motors can be overloaded easier at low speed. Is there any temperature indicator on the motor? This may give a second symptom of overload.

Are your rocks bigger or tougher than specification? Change of rock supplier or source? Is the feed rate what it should be?

Have you asked the drive supplier if there is a recorder you can hire to get definite information on the loading profile and if/when it is excessive?

Has he any suggestions for measurements?

Is there an ammeter or other guide to load magnitude or profile?

This is a good troubleshooting guide.....note that an incoming voltage imbalance of just 3-5% can cause the drive overload to trip...so the first thing to check is probably the quality of the power being supplied and record it's performance if possible...

http://ecmweb.com/ops-amp-maintenance/troubleshooting-your-vfds

Has the actual temperature of the IGBTs been measured? Are they "truly" overheating?

Has anyone tried extra cooling? Did it help?

Talk to the VFD mfr. Some will detect over temperature at the IGBT by using individual thermistors or RTDs at the IGBT modules, some have one or two placed strategically on the heat sinks, some just estimate the heat based on rate-of-rise in current. Without knowing how it is determined, there is no meaningful help you can get here.

Generally speaking, if your VFD tells you exactly WHICH IGBT is overheating, it is the type that looks at each module individually. If that's the case, it could be a defective IGBT, or as mentioned, a defective temperature sensor.

If the alarm is general and does not distinguish which module, it's more difficult to determine the issue. But one common issue is excess DC bus ripple. That can be the result of a failed or failing DC bus capacitor and must be fixed before you lose ALL of your transistors.

Again, speak to the mfr of the VFD, they will know best.

Dear Friend,

We had a similar problem of tripping of vfd was frequent ( vfd is reputed multi-national company) and some times, re-starting will take much time to re-start. First the vfd manufacturer claimed that AC effect is not sufficient and the Temp. of the room was found to be 23 Deg.C when the room temp. recommended is 25 Deg. C only. The real problem was the heat liberated by vfd was more than the design value.

You have to find out (or ask the supplier )what is the percentage of heat liberated by your vfd. and if the actual heat liberation is more than the design value - your problem will continue and replacement by new one will not help.

After struggle for 2 months - they found "internal wiring sequence " was wrong and they found that 2 components were by-passed. . How it happened - the vfd manufacturer could not explain, and because of their fault, we sufferred a lot.

Further the earthing should be independent, not connected to any other equipment and earth flat area should be 2.5 times more than the normal area. Pl. check for this also.

After attending to the internal wiring sequences, identified their Design Dept. Head, the problem was solved. Pl. discuss with your vfd manufacturer to examine this point in consultation with their design dept. and this may solve the problem.

DHAYANANDHAN.S

ref links...

https://www.physicsforums.com/threads/explain-the-basic-concept-of-igbt-inverter.415719/

http://www.fujielectric.com/products/semiconductor/model/igbt/application/box/doc/pdf/RH984b/REH984b_04a.pdf

Is this a fluid-cooled drive?

If so, I would verify the cooling fluid is circulating at the correct speed and is being properly cooled by the heat exchanger.

If circulation & cooling of the fluid is ok I would test the fluid conductivity and resistance properties to make sure all is within specifications.

You must use distilled water in water cooled systems and in no instance can de-mineralized or tap water be used.

I had this problem several years ago with an ABB vfd. Actually, my customer was having it. Turned out the power that the customer was feeding the vfd would have spikes, over-voltage of only a few sine waves. This would cause the self-diagnostics to flag an overheating error code. Even after changing the parameters to ride through the spikes, we got the same error codes. Had to switch to a different vfd that would ride through power spikes, as it was not possible with the one we had specified for the customer's load driven by the vfd.

Would it be your VDF is under capacity for your 250KW motor.?? If the design of the VDF capacity is lower then your 250kW motor the your IGB will be over heated during operating. What is your VDF output capacity,?

Yes. The first thing to do is to open a dialogue with the <...VFD...> manufacturer. CR4 does not provide training in the use of the telephone, though, so this will be by others.

The next things in the <...procedure...> will depend upon the outcome of the first thing, which cannot be determined from here.