Shaker Table Validates Earthquake Detection, Shutdown

Field Testing Seismic and Vibration Monitoring Systems

A: The goal was to give hydro power instrumentation & controls or reliability teams a product with which they could test their vibration protection systems at machine running speed. Machinery in the hydro power market runs at slower speeds than other vibration applications such as gas turbines. Running speed is one of the primary frequencies at which vibration issues develop. By simulating vibration at slow speeds, technicians can have confidence that the instrumentation at alarms will respond if and when they are really called upon for a warning or shutdown.

A: Vibration is one of the primary ways industrial plants monitor the condition of machinery and protect against unplanned outages. It also warns us of potentially dangerous machinery conditions thus keeping safe the personnel working around the equipment. Dangerous consequences exist on many levels if industrial machinery breaks down. The vibration protection system is the first line of defense, and it is critical to make sure that the entire system is working – not just by testing the sensor instrumentation, but making sure alarms trip at the right time and displays are scaled accurately.

A: Yes, nuclear plants have seismic activity protection systems that are based upon vibration measurements. Potential earthquake activity is a low frequency event. Very sensitive accelerometers capable of detecting slow speed ground vibrations are used. Recent global events have shown the consequences of the seismic system not providing adequate protection. But also in contrast, consider what happened at North Anna Nuclear Power Station in 2011. The plant was properly shut down when a seismic event was detected. Aside from the obvious safety benefits and uptime, consider how the company benefited as a whole, inspiring confidence in the community and allowing it to continue to grow.

A: As odd as it might sound: portability. You were probably expecting a more technical answer but the truth is The Modal Shop is the first company to bring slow speed calibration out of the lab and onto the plant floor. Sensor manufacturers use a long-stroke shaker to test accelerometers at slow speeds before shipping. But these test systems are not portable. Until now, testing the sensors required removal and return to a calibration lab. In that case only the sensors are tested, not the entire monitoring system. We have taken the calibration lab and put it in the hands of the field technicians, allowing them to bring it to the sensor and test the entire measurement channel.

A: The Modal Shop, an Amphenol Company, has a long history of calibration and measurement excellence to share. We are a small company located in Cincinnati, Ohio – the world leader in vibration calibration systems. Our laboratory grade systems are used in national metrology labs and Fortune 500 companies around the globe. Our portable systems are rapidly earning their market-leading reputation and popularity in power generation and oil and gas circles. We are also a calibration service provider accredited to ISO 17025 standard by A2LA. We have practical experience calibrating hundreds, if not thousands, of different vibration sensors.