eNext blog

Repair, don’t replace – generators can continue serving decade after decade

Gabor Csaba 13 December 2021, 14:54

A generator is a technically complex piece of machinery designed for long life. Repairing and modernising an existing generator rather than buying and manufacturing a new one, always makes sense – and it promotes sustainability. With attentive maintenance activities, generators can continue serving decade after decade.

A close-up of a newly manufactured ASEA GTP-type rotor painted forest green.

All operators in the energy sector need to optimise operational efficiency and minimise costs in order to stay competitive and profitable. A generator is crucial in the process and a very expensive piece of machinery, which makes it difficult to replace. Therefore, from an economical point of view, repairing the generator is advantageous as long as there are components and a skilled service supplier available.

For one hundred years, the Swedish company ASEA – later ABB – has provided factories and power plants around the world with different types of generators. One type of generator widely in production was the GTP-type. Approximately 2000 ASEA/ABB GTP-type generators were manufactured between 1920–1988, and we estimate that around 500 are still in operation around the world.

Rotors of this type are a unique design that Fortum eNext happens to know very well, because they were manufactured in a workshop in Västerås, Sweden, where we today run a dedicated workshop for generator maintenance services. This type of rotor has not been manufactured in nearly 40 years, but the engineering know-how of the technology of how these rotors are designed and how they should be rewound and high-speed balanced has been maintained at our workshop.

The technical lifetime of a generator is around 30 years, but in fact they can run much longer than that. Manufacturing new components and rewinding are two ways to prolong the lifetime. Customers from literally the other side of the world have shipped us their generator rotors for service. We were even able to offer a customer in Brazil the delivery of a completely new rotor based on the original design, but enhanced with upgrades and modern materials.

We can also introduce improvements in both the design and the process of rewinding. The ability to do calculations on the generator’s electromagnetic side is the key here. When working on an older machine, the calculations have to be replicated because the exact same materials are no longer available. So we have to update the design and calculate the complete generator according to today’s material and requirements. Fortum eNext is one of the very few service providers able to also offer stator rewinds for this type of generator.

With specialised engineering, generators can remain in service for many more years. Our philosophy is that it always makes sense to repair and modernise existing equipment rather than buying and manufacturing new. As an OEM-independent service provider with technical expertise and workshop skills – and with more than 30 years of experience in generator services – we are able to modernise and repair equipment and technologies from many different suppliers.

Gabor Csaba

Gabor Csaba

Ph.D., Principal Generator Specialist
Tel: +46 76 783 4933
gabor [dot] csaba [at] fortum [dot] com

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Designing and manufacturing a completely new GTP-type generator rotor

Operation and maintenance

Another ASEA GTP-type rotor rewound and redesigned at Västerås generator workshop