ABB ACS400 drive giving FL4 fault indication without load connected without motor w ?

ABB ACS400 drive giving FL4 fault indication without load connected without motor connected to the output ?

Generating DC Bus Voltage ...... as the frequency starts to increase from 0 till 4 Hz the fault appears ........

FL04 means " short circuit " as the manual explains ...... checked all the motor cables, motor windings, input supply

its connected with a turbo mixer having the specs of the motor as :

45/52 KW

0.86/0.86

50/60 Hz


Has the winding resistance of 0.06 ohms between each of the 3 windings

Would be the case of shorted IGBTs ?
What kind of IGBTs or SCRs are present in this drive ?

thanks

Could be IGBTs or the output filter?
If the drive has been used down to "0" HZ then it is capable of supplying the motors at their stalled current. So there is normally a current limit just above this value to protects the motor against a mechanical overload (spanner in the pump!??) but it sounds as though its not the motor current thats the problem. can you see if the DC bus voltage is OK?, if an IGBT is faulty then the DC bus will be absent or low.
Frank

DC Bus voltages are about 540 V dc ..........

ACS 400 Frequency Converter
User’s Manual information.....

FL 4 SHORT CIRCUIT
* Fault current:
• Short circuit.
• Power supply disturbances

Possible reasons for this fault are:
• There is a short-circuit in the motor cable(s) or motor
• Supply disturbances

Because we dont have any schematics for this VFD.
so general repair rule , check first all power components and bus capacitors.

here’s a list of the most common failures.

Loose connections.
Its a number one cause of VFD downtime. Check simple stuff first.
Is a plug on the main circuit board loose? Try that first, before trying a more complex VFD repair.

Cooling Fans.
Major cause of problems.
Some VFD s will let you know about this, but most won’t until you begin tripping on over temperature.
The over heating can and almost certainly will cause major issues long term, so check this often.

Electrolytic Capacitors.
These have relatively short lives compared to other components, and, overheating shortens it even more.

Power Semiconductors.
These are less common, but drastic failures.
If this happens, do NOT just replace the IGBT or Diode, find out why if failed.
Or, you’ll likely just be replacing it again as soon as you power up.

VFD Software or programming.
Was it running before you tried changing a parameter? Then put it all back to where it was and see if that fixes it.
Don’t automatically install factory suggested software revisions until you back up what’s running.
In general, if its running fine now, leave the programming alone.

Circuit boards.
These are much less common failures than one might think,
but is often the first thing suspected when an inexperienced technician begins to repair a VFD.


Variable Frequency Drive (VFD) Troubleshooting and Maintenance
**broken link removed**

Troubleshooting a Variable Frequency Drive
https://www.newark.com/pdfs/techarticles/agilent/TroubleshootingVFD.pdf

the fan is running fine ........... blow away the dust & clogged dust particles with a air blower ........

connections were tight .......... how to check the bus caps ?

how to figure out the cause of dead or bad power semiconductors if there or of diode if there ?

Quick and Easy Steps for Troubleshooting a VFD
**broken link removed**

how to check the bus caps

Click to expand...

With power removed from the drive, a physical inspection of the capacitors should not show
any deformation of the cases of the capacitors or liquid leaking from them.

Low voltage capacitor testers are of no use in checking DC bus capacitors.
The mainconcern is to ensure that the capacitors don’t have excessive leakage current when the DC
bus voltage is applied to it.
This cannot be tested at a low voltage.

If one capacitor on the DC bus is found to be weak or damaged, it is important to replace the
entire capacitor bank.
A capacitor with an excessive amount of leakage current places excessive stress on other capacitors in the bank.

how to figure out the cause of dead or bad power semiconductors

Click to expand...

check is there any marks of breakdown or heating, any marks of mechanical fail in components.
any of above in outer circuits , cables or components.
The aging of the component. ( Reason: Bad cooling, too high temperature, continous overload )

this drive is programmed in such a way that it drives a heavy torque mixer automatically controlling its output torque & hence the speed that it gradually increase to its maximum rpm till the output voltage of 400 Vac or 404 Vac to the motor .....

there's no controlling via any pot . to set or increase or decrease the rpm ......

what type of IGBTs or power modules are present in this ? Any electrical diagram ??

---------- Post added at 16:01 ---------- Previous post was at 15:39 ----------

Suddenly the fault disappeared itself ......... and the drive with & without load is working fine without no fault alarm without no error ....... what the hell did happen to it ? I couldn't understand the fact

its connected with a turbo mixer having the specs of the motor as :
45/52 KW / 0.86/0.86 / 50/60 Hz

Click to expand...

Biggest motor size in ACS400 series is 37kW

what type of IGBTs or power modules are present in this ? Any electrical diagram ??

Click to expand...

I could not found any block - or schematic diagrams about ABB ACS VFD´s.

ABB Download Center for All Categories
ACS 400
https://www.abb.com/abblibrary/DownloadCenter/Default.aspx#&&/wEXAQUDa2V5BWEzwrBSb290wrFBQ1M0MDDCscKxwrHCsVTCscKxMMKxZW7CsTI5wrFGScKxwrEywrFUwrEwwrHCsTDCsTHCsTIwwrEyMMKxMcKxwrHCscKxwrFSb290wrHCscKxwrExMcKxVT73I0BOSD+mGzlXwYF+bJK3iXE=

Suddenly the fault disappeared itself ......... and the drive with & without load is working fine without no fault alarm without no error ....... what the hell did happen to it ? I couldn't understand the fact