Motor 1 field exciter low (under-) current.
Check:
− The settings of 31.57 Minimum field current trip delay and
31.58 M1 field current low level.
− The settings of the EMF controller, flux linearization and field
current controller in group 28 EMF and field current control.
− The motor nameplate for minimum current at maximum field
weakening ≡ maximum speed.
− The field circuit fuses.
− The field auxiliary supply voltage.
− The field contactor is not closed.
− If the field current oscillates.
− If the motor is not compensated and has a high armature
reaction.
− For fault messages at the field exciter itself (flashing LEDs),
04.26 M1 field exciter fault word and 04.36 M1 field exciter
warning word.