Enclosed picture of turbine blade from a ABB VTR 454-11 rotor taken out for standard revision and overhaul. Turbocharger was close to complete failure due to passage of foreign objects. Passing through the nozzle ring the fragtments have damages turbine blades, normally this would be repairable by welding and machining, but in this case the turbine blades were scrapped. The blades have taken a big hit next to the damping wire causing cracks between damping wire hole and edge of blade. With continued operation this would have caused complete failure of turbocharger. The tip would have cracked of during operation (10 - 12000 rpm) causing heavy unbalance. The turbine bearing would them collapse, and thereafter the compressor side bearing. In best case scenario engineers would have been able to shut down engine in time, worst case total loss...

How big is this rotor?

Normally fitted on example WARTSILA 8L46 and MAK 8M552C... On the larger four stroke engines...
Bu the scenario is the same for smaller turbochargers..