Semiconductor Fuses Are Blowing Frequently

If it is a reversible drive, please check the circulating current.

Check for loose wire on the gate driver synchro of accumulated dirt that could produce un-controlled firing angle from vibration...

Do a wire pull test on all of the drive control wiring. (Turn the power off first...)

There could be an intermittent in the electronic boards too.

You might need to push on different areas of the boards with an insulated rod during operation to see if you can trigger the problem. Apply reasonable force and be extremely careful. Make sure that the rod is long enough to keep you out of danger. This procedure might be illegal in you area. Check first.

aR fuses are not overload protection fuses but Short-circuit protection so will fuse before the Semiconductor(s) is damaged. Its I(Squared)t is much shorter than of semiconductor.

<<3. Most fuses blown at the time of Main power failure. >> this is normal as the malfunction of electronics on powershut downs.

Now I have read a new type of semiconductor overload protection fuse marked gR which new for me.

Heat is the greatest and most common threat to electronics. Are the air vents, heat sinks, and cooling fans clean and functioning properly. Are the drives located in a place prone to dust and dirt accumulation. Compressed air in hands of a qualified technician may be all that is needed to restore proper air flow. Avoid solvents.

Mr. Redfred all drives are installed in properly ventilated with cooling blower so heat factor is very low. All drives also contains a line reactor in its incoming ckt.

Its lil confusing that fuse are blowing on the drives which are not in service ie they r just power ON and no load is connected across them. If there is some problem(short circuit) in incoming side then it shouldn't affect the fuses connected on outgoing side. Incoming side is protected with ABB ACB. Drives are not situated in vibrating place.

I understand that it is confusing to have parts fail that should not be seeing any current at all. All that this means is that the circuit is not what you expect it to be. You must initially forget your ideas about how the circuit should work and safely test to see how it is working. If you measure the current through these fuses, when they blow, and find that the current never exceeds 630 amperes then you may have defective fuses, counterfeit fuses, or your testing procedure is imprecise. More than likely you will find that higher than expected surge currents are actually happening. The duration and conditions that trigger these current spikes may help lead you to discover the root of your mystery. They may only trick you to better understand how your system works.

What you have here is a mystery. The only way a mystery can be solved is with more information. We can help you analyze that new information but we cannot provide you with the information itself.

"ventilated with cooling blower so heat factor is very low"

Although the system's circuit boards are being cooled down by a fan or a blower and temperature inside your controller box has been normalized, it is very possible that a lot of dust has also accumulated, coating all over your electronic components. I had experience this same scenario, specially in a very humid conditions that sensitive fuses will unexpectedly blow as triggered by the combination of dust accumulations and high humidity! It is also a good preventive maintenance practice to include vaccuming as an added step during that process. The dustier the area the more the cleaning frquency required. It will save you a lot of time and unnecessary headaches!

I am extremely proud of my ability to solve problems remotely.Vsar has experience, with a problem similar to your's. I hope we can help. Please shut down the power, discharge all the capacitors (if needed), and examine the components of your drives, for the accumulation of dust or dirt. Clean is really cool. I wish you the best of luck with this mystery.

A spike or surge occurring on the primary power reticulation network is not uncommon during a power interruption event.

Your reticulation network would be loaded by all manner of loads just prior to the event, many of them would be reactive. The back EMF of these loads will momentarily energise your network when the power is disrupted. The energy is dissipated through all connected loads.

Even though your DC drive is iself unloaded it would still be connected to the primary power reticulation network, ie the "idle" DC drive is still a load through which the back EMF will dissipate.

What other loads are on the same branch circuit as that supplying your DC drive? Is your facility equipped with surge reduction filters?

http://en.wikipedia.org/wiki/Thermistor

only use if your DC network has no overcurrents

(i speculate (far assumption) the DC net developes short time power demand to whitch the DC Power Supply can't respond - fast enough - so it provides short term overvoltage just after the demand - that causes a secondary 1 - so the thermistors are needed before the DC Power Supply - so it cant go nuts - ? bad system DC network design ? - /!\ it's a high time speculation /!\ - someone has to verify)

CONTACT THE EQUIPMENT MANUFACTURE AND GET HIS ADVICE.

Years ago, the fast blow fuses cost more than the devices they were protecting. It was cheaper to use ordinary fuses and let the SCR's or transistors fail. The SCR's or transistors frequently had higher current ratings than the fuses and they didn't fail.

Hello did you ever find out what was causing your fuses to blow? I am presently having a similar situation at work, fuses blowing as soon at about 650 amp whereas the drive should be able to supply up to 2000A, depending on the current limit setting.

The drive can assign to a few dc motors but usually fuses blow when one particular motor is assigned, but it has happened as well when running a different motor (above 600a). This motor has been changed out 3 times.

The set up is 2 x 700v 700A fuses in paralell on each supply phase to the bridge. Multiple fuses have blown.

From reading experts below I am now thinking one of the capacitors or maybe dust may damaged one of the cards. I was looking if noise might be on the com line but the other drives are ok.

Any help would be great.