Cause : Fault in the field circuit. The line voltage RMS value calculated from the area of each network half-wave (rectification average value * peak factor) must be greater than the response value for phase failure monitoring.

Possible fault causes
♦ Threshold for phase failure (P353) set incorrectly
♦ Undervoltage / overvoltage threshold (P351, P352) set incorrectly
♦ Field phase failed
♦ Line contactor opened during operation
♦ Fuse blown in the field circuit
♦ Field current controller and/or field current precontrol not optimized or badly optimized (check P112, P253 to P256; possibly execute current controller optimization)
♦ Check P396 (field current monitoring threshold) and P397 (field current monitoring time)
♦ If the fault value is 6: Offset fault in the actual field current value sensing, relevant parameter: P825.i01-i03 (Offset depends on P076.i02) or P394, P395 (Threshold and hysteresis for message I_field < I_field_min) must be checked
♦ If the fault value is 7: Circuit for the "new" field direction is interrupted (e.g. because the contactor for "new" field direction does not pick up), P398, P399 (Threshold and hysteresis for message I_field < I_field_x) must be checked.

1 Voltage failure occurred in the field supply (terminals 3U1 and 3W1) (if P086 = 0)

2 Delay time according to P089 elapsed in state o5.1. Wait until the voltage and frequency at the field power section are within the tolerance range (P351, P352, P353, P363, P364).

3 Delay time according to P089 elapsed in state o5.0
Wait until IField act (K0265) > 50% of the instantaneous field current setpoint K0268 [as of SW 1.9, can be altered by means of P396] and until "I Field extern > I f min" (see P265)

4 After P086 > 0 has elapsed (time for automatic restart) in operating state ≤ o4:
Voltage failure in the field supply or IField act (K0265) < 50% IField set (K0268) for longer than 500 ms [as of SW 1.9, can be altered by means of P396 or P397] or "I Field extern > I f min" (see P265)

5 When P086 = 0 (no automatic restart) in operating state ≤ o4:
IField act (K0265) < 50% IField set (K0268) for longer than 500 ms [as of SW 1.9, can be altered by means of P396 or P397] or "I Field extern > I f min" (see P265)

6 If field reduction before field reversal, I_field ≤ I_field_min (P394) is not reached within 30 s

7 If field build-up after field reversal, I_field > I_field_x (P398) is not reached within 30 s