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Machinery protection system scope expanded to serve turbine upgrades

The ability to quickly identify issues affecting the performance of rotating plant as well as being able to optimise dynamic behaviour is vital to all plant engineers. Established monitoring systems like the Sentry G3 machinery protection system from Sensonics combines the flexibility of hardware in a single module type for all sensors. The system is compliant to API 670 so meets the most stringent protection requirements, in addition to meeting IEC 61508 up to SIL-3 standards.

The Sentry G3 system is being continually developed to meet the ongoing challenges and also those arising from specific applications, such as for turbine upgrades at major UK nuclear power stations. For these applications ‘Emphasis’ audits are considered to be the most complex and rigorous (for software) and users will be assured that Sentry G3 meets these standards.

The emphasis method assesses a device’s compliance with IEC 61508 for functional safety standards, along with other requirements specific to the UK nuclear industry. It provides end-users with the confidence that both the hardware and software components in these protection systems meet the required high levels of design, testing and production which minimises the risk of systematic failures.

Advanced features include: vibration, position and speed parameter trending facilities, including log and view of up to 60 days of data, ‘look back’ at trends and alarms, plus download data for further analysis in Excel. It is also now possible to directly view proximity probe gap and vibration transducer bias voltages, to verify correct transducer operation and calibration.

The Sentry G3 single module concept minimises the need for spares holdings, helping to reduce ongoing maintenance costs while also lowering the risk in retrofitting applications where the need to interface monitoring systems quickly and correctly with previously installed sensors is key.

The system is software programmable and -upgradable, which is said to ensure adaptability in future as application requirements change. It’s also expandable by adding additional G3 monitors. Up to 24 measurement channels are housed in a 3U x 19” rack-mounted format. Multiple outputs are available on the back of the rack for up to three alarm levels and two analogue outputs per channel. Dual redundant Modbus communications to a module level provide a communication system, while the in-built LCD display offers readings, sensor integrity voltages, trending and FFT, all of which confirm the accuracy of the installation.

In summary, Sentry G3 provides state-of-the-art, flexible, easy-to-install and maintains space-saving protection for the following modes:

Measurement - Absolute bearing and relative shaft vibration, shaft position and thrust wear, speed, phase and reverse rotation, differential and casing expansion, rod drop and temperature.

Turbine specialist measurement - Shaft eccentricity, order tracking, dynamic pressure and mark - space differential expansion.

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