Damaged generator rotors: the economical and logistical benefits of repair over scrappage

Many would agree that one of the worst possible electrical failures on a generator rotor is a motoring event while the rotor is at standstill. The resulting damage can be extremely severe – including a melted rotor body and double earth faults. In many cases, this renders salvage impossible and the rotor has to be scrapped.

This paper describes extensive repairs recently carried out by Quartzelec to a generator rotor following such an occurrence whilst the rotor was at standstill. The failure resulted in a double earth fault and severe arcing damage, which included deep excavations within the forging slots, almost 20% of the copper winding on the rotor melting away or becoming severely distorted, and severe damage to the retaining rings, snap rings and wedges.

Damaged generator rotors:
the economic and logistical benefits of repair over scrappage.

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