CASE STUDIES - RUSSIA

Largest Power Station in the World
On-site Repair in Siberia, Russia
Machining Alternator Rotor Hydrogen Seal Diameters and Bearing Journals

 

In-Situ Machining Solutions (UK) Ltd have recently completed major repairs to a large steam turbine alternator rotor journals and hydrogen seal diameters which had suffered circumferential wear grooving over years in operation.

 

In-Situ Machining Solutions (UK) Ltd were contacted by a well respected European generator manufacturer to help in refurbishing the worn diameters of the alternator rotor during a complete upgrade to the rotor core at a large power station complex in an isolated area of Western Siberia, Russia.

 

The on-site machining project consisted of machining four diameters - two diameters were bearing journals Ø520 x 675mm long and two hydrogen seal diameters Ø520 x 250mm long,  positioned at  the Drive and Non-drive ends of the 14 metre long x 80,000kg alternator rotor. These were to be machined undersize to allow the fitting of repaired undersize bearings.

 

Due to the shear weight and length of the rotor, logistics and geographical positioning of the power station made transporting the component to a factory for the repair almost impossible. The customer had no alternative but to carry out the work on-site which was by far the most cost and time effective means of executing this project.

 

Using one of In-Situ Machining Solutions (UK) Ltd standard orbital turning machines, the routine work was conducted in our usual  professional and methodical manor. Initial stock removal was followed by a superfinishing and polishing operation. The work was carried out to exacting standards to pre determined sizes given by the generator manufacturer.

 

All diameters were checked using calibrated measuring equipment and were found to be within the limit and fit requirement. Flatness of the diameters were checked with straight edge an engineers blue gave a better than 90% bluing transfer. Surface finish attained ranged between 0.2 & 0.3 being better than the 0.8 Ra µm design requirement. The completed work was finally inspected and passed off by our clients metrology department sent especially to site for this verification exercise.

 

This particular machining exercise was conducted with the rotor dismantled from the stator but can also carried out when the rotor is in place.

 

A tight schedule meant working long hours to complete the job in two weeks, and our customer and end user were completely satisfied with the work carried out.