How To Choose Vibration Sensors

How To Choose Vibration Sensors

With so many different types, shapes and sizes to choose from, selecting the right vibration sensors (otherwise known as accelerometers) for your operations can be a challenging task. It is, however, essential. To ensure you specify correctly, there’s a number of important factors you need to consider.

Vibration range and sensitivity – The range of vibration varies greatly from operation to operation. You should always specify vibration sensors to measure the maximum vibration range of your specific application. In a standard application (50g range), the sensitivity of a typical vibration sensor is 100mV/g, while in low vibration applications (10g) the sensitivity is 500mV/G.

Vibration frequency – Knowing the frequency span you need to measure is as important as knowing the vibration range. The frequency spans are dictated by the fault frequencies of the fastest-turning component in the machinery being monitored. The frequency span of a slow turning ball mill, for example, will be narrower than that of a high speed fan.

Environmental temperature – After poor and incorrect mounting, the greatest threat to the performance of vibration sensors is the environment. High temperatures can affect the operation of the electronics. However, charge-mode accelerometers are specially designed to work in applications with very high temperatures.

Contact with chemicals or debris – This can reduce the reliability of results and should therefore be considered carefully. To ensure performance and results are unaffected by exposure to chemicals or debris, accelerometers with corrosion and chemical resistant stainless steel bodies should be specified.

Hazardous atmospheres – Hazardous environments are those that contain flammable gasses or vapours, combustible dusts, or ignitable fibres, where even the tiniest spark could cause a fire or explosion. To protect people, machinery and productivity, you need intrinsically safe accelerometers, which are specifically designed for use in hazardous areas. They deliver the same level of performance as their non-intrinsically safe counterparts, but do so by using a lower level of energy.

Immersion in liquid – The average accelerometer isn’t constructed to be waterproof. If your application requires accelerometers to be exposed to liquid, the solution is to specify vibration sensors with integral polyurethane cables. This prevents liquid infiltrating the accelerometer and affecting the electronics – whether the sensor is at minimum sprayed with water or even completely submerged in liquid on a permanent basis.

Exit and profile – The exit and profile of a vibration sensor has minimal impact on performance, but if not considered can become a frustration for those responsible for maintenance. Depending on where the vibration sensor is located, you can choose between a top exit, side exit or low profile connection to allow maintenance engineers easy, safe access.