its runaway condition which might occur when there is sudden change in flux field.if suddenly flux becomes zero it will lead to a very high 'w'(omega) so as to maintain constant back emf.this high speed is not desirable for the armature and will lead to severe damage
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its runaway condition which might occur when there is sudden change in flux field.if suddenly flux becomes zero it will lead to a very high 'w'(omega) so as to maintain constant back emf.this high speed is not desirable for the armature and will lead to severe damage