Aratiatia G2 Runner Overhaul
Some of the equipment used at the hydro station was recently repaired by AIE:
- The turbine runner was cracked, had cavitation damage and was badly eroded
- Sealing diameters were machined then weld overlaid with a wear resistant material
- Wicket gate sealing strips were weld overlaid. Erosion damage was repaired and the sealing faces were completely re-aligned by CNC machining
- A new fabricated Bottom Ring was manufactured in our Okuma CNC machining centre using erosion resistant materials. The ring was 4.5 metres in diameter with 20 accurately spaced holes in a PCD around the centre for the wicket gate locations
The runner weighed almost 40 tonnes, but we were able to manoeuvre the runner through the AIE workshop without a problem thanks to the two 25 tonne overhead Gantry cranes in the fitting and fabrication areas. We also utilised our special purposes lathe to turn the runner in our workshop.