hello

We have a 20hp speed control. santronic g3 (yaskawa g series may be) It gave a Fu error. An n channel mosfet burned and the dc dc converter card capacitor exploded, we replaced them but we still continue to get the same error. The dc bus voltage returned to normal, around 580vdc. The user manual says the dc bus fuse is blown but there is no error there. I suspect the dc dc card. 580vdc ec enters and 320 vdc comes out, I don't know if it should be a different voltage.

Thanks in advance for your help. Which forum can I get help regarding driver repair?

 

320V DC seems unusually high, unless it's stepping down the 580V to an intermediate bus... If possible, replace the DC-DC card.

 

Did you check the model number of the burnt MOSFET and replaced that with a new one of that same model?
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yes

 

320V DC seems unusually high, unless it's stepping down the 580V to an intermediate bus... If possible, replace the DC-DC card.

https://www.ebay.com/itm/264509151113

This is the card. It has this on it 2sc3536 npn transistor.The capacitor here has failed.

 

Chopper card

 

OK, from the supplied circuit schematic it is clear that this is not a simple product. It may be that additional components on the various modules have also been damaged by the triac failure.

 

Chopper card I applied 24 vdc to the card, it outputs a value like 23 vdc, it seems to be doing its job. When it goes above 320vdc, it seems to fix 320vdc..