Vacuum chamber investment improves performance and reliability

Siemens is to invest £4 million in a major upgrade of its vacuum chamber in Newcastle where the balancing, overspeed and testing of rotors takes place.

This vital facility gives plant operators confidence in the integrity of their rotors as well as the assurance that minimal balancing will be required once they are returned to site, thereby speeding up the return to service and reducing costs. Nigel Presley, who heads the Balancing team, explains the refurbishment will take advantage of some of the latest Siemens technology. “The Siemens condition monitoring and remote diagnostics package will mean we’re able to continuously monitor the performance of the new drive system.


Nigel’s team balances and tests steam and gas turbine rotors, compressor rotors, generator rotors and exciter rotors. Its capabilities are often called upon as part of an overall service package but it also provides a standalone service to power plant owners and other service facilities.As one of only two such facilities in the UK, the vacuum chamber balances and tests many machines produced by third party manufacturers, as well as Siemens and Parsons equipment. The upgrade will ensure the continued reliability of this essential asset. “Some of the current components are past their original design life and becoming obsolete, with considerable lead times for alternative replacements. We needed to invest in the vacuum chamber before that posed an unacceptable risk.”


Alongside improved reliability the investment will deliver improved performance. “The current acceleration rate is lower than we would like for some of our larger turbine rotors with free-standing blades,” says Nigel .“Greater acceleration will also mean we can pass through resonant frequencies for the minimum time possible during the run-up to overspeed, which reduces the strain on the machines.” As well as a drive system and gear box the upgrade includes a completely new digital control room that will give the team much greater visibility of everything happening in the vacuum chamber. The switchgear, transformer, converter, motor and condition monitoring system will all be the latest Siemens technology.

All of the data gathered will be analysed using Siemens X-tools and hosted on MindSphere, the Siemens cloud-based platform. That means that we’ll be alerted to any potential issues with the system before they occur, and that they can be diagnosed remotely by an engineer anywhere in the world. That’s a huge benefit because it means we can schedule preventative maintenance and minimise any machine downtime.
Nigel Presley, Operational Manager

Other investment dividends include improved safety for the operators due to the elimination of many manual tasks, plus greater protection for the rotors as a result of a new lubrication system and the increased monitoring of oils, temperatures, pressure and vibrations. In addition a new transport bogie will convey the rotors from the adjacent bay into the vacuum chamber, which will be much safer for both the operators and for the customers’ rotors.


“The upgrade will also allow us to balance and overspeed a wider range of rotors,” conforms Nigel. “Better speed control will mean we can balance smaller industrial rotors, while the increased power of 6MW will allow the running of larger turbine rotors – up to 12.5m2– at much greater acceleration rates.”


As well as the balancing required after any service work has been carried out on a rotor, Nigel and his highly experienced engineering colleagues can also carry out more detailed vibration diagnostics for specific problems, such as blade excitation telemetry testing for analysing the resonances of individual blades. “Our customers depend on these capabilities and this latest investment in the vacuum chamber means we can continue to offer them well into the future.”The four-month upgrade begins next year with the new facility due to be commissioned in May. “Our priority has been to give our customers as much warning as possible and to carry out the work during the quieter time of year.”

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