Due to Wyko's knowledge of repairing many types of turbo rotors, their team picked up on the fact that they may have not been specifically designed for the application, and further investigation identified insufficient insulation for the application as one of the main reasons for failure.

Overhauling the 15tonne units involved complete disassembly, annealing, cleaning, non-destructive testing and condition reporting on every element of the coils. To prepare the rotor body to accept the new rotor coils, it was cleaned and all insulation removed from within the slots.

Electrical tests were carried out to ensure integrity of the rotor laminations and a full mechanical datum check of the rotor body, rotor slots, rotor shaft and coupling also conducted.

Wyko's Newcastle upon Tyne workshop manufactured the specifically designed rotor slot insulations, which were supplied to the Wyko EMS Chesterfield for insertion into the rotor body, prior to the fitting of the rotor coils. The rotor coils had also been insulated and had met the designated class H temperature classification (180infinityC operating temperature). Following completion of the rotor rewind and reassembly, electrical tests were carried out prior to stoving and curing of the rotor winding. After the curing cycle, further electrical tests were then carried out before and during a 20% over-speed dynamic balancing operation.

Wyko is one of the largest suppliers of maintenance and repair products and services in the UK and boasts one of the most highly qualified teams of engineers in the industry. Other Wyko services available include mechanical engineering, electrical services, condition monitoring and generator services that are available to general industry and marine customers across the UK.

www.wyko.co.uk