MASTERDRIVE 6SE70 (CUVC)
Rectifier unit MLFB :6SE7041-3HK85-0AA0
Regenerative Rectifier unit MLFB :6SE7041-3HK85-1AA0
Inverter unit MLFB :6SE7041-1WL86-3AE0In a 12 pulse operation we have 2 rectifier units, the first is main rectifier and the second for regenerative rectifier and an inverter unit(6SE70) . Motor power is 1700 kw for filter fan application.The converters are fed from a 3 winding transformer, incoming 725v ac,50 hz. It is working fine upto 500 Rpm taking 600amps of current at no load, but if run the motor at 600 or 700 rpm, it is tripping with F008(Undervoltage ) fault on the inverter unit and with F033(undervoltage) on the rectifier unit (which are connected with CUR card) . But it is tripping after 24 to 36 hours of running everytime. I have checked the incoming DC voltage in r006, it is in between 918 to 945 v dc. I have changed the CUR cards, on the rectifier units but it is still giving the same fault. I have checked the capacitor and thyristor modules individual testing with a 12v battery, meggars taken, and found healthy.
Drive is running in (F reg) mode. Kinetic buffering is OFF.
1.P71 : 690 v ac(Rectifier unit)
2. P71 : 690 v ac(Regenerative Rectifier unit)
3.P71 : 930 v dc(Inverter unit)plz suggest me do i need replace any other cards.Herewith I have attached the backup files, plz find it.
Plz suggest me to trace out this fault.