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The paper examines transient torque phenomena which can arise at LP turbine blade roots and at shaft couplings of large synchronous-generators following a grid network disturbance. Fault clearance and faulty synchronisations for two 3000 rpm 660 MW turbines and a 3600 rpm, 300 MW turbine is examined. Peak torque at various shaft locations and at the LP turbine final-stage blade roots is computed as a function of the fault clearing time or the synchronising angle respectively. Stresses induced at LP turbine blade roots where the shaft system is protected against excessive stress by use of a turbine/generator shearing coupling is examined for one turbine only. Sustained 3-phase and line-to-line faults at the generator stator terminals are also considered.