Velocity Sensor

A 3.94 mV/mm/s piezoelectric velocity sensor, Meggit’s PV 102 has CE approval for the uncertified and ATEX, IEC and CSA hazardous area certifications for the certified versions. The latter certifications are commonly required in the nuclear and fossil power generation, oil and gas, and petrochemical industries. Brazilian INMETRO approval is expected later in 2011. The device is ideal for condition monitoring of motors, pumps, fans, compressors and turbines, including steam and gas (aeroderivative and frame) turbomachinery. It may be used to compliment proximity probes in a condition monitoring or protection system. The standard output of the device is fully compatible with systems currently employed in industrial environments, such as the company’s VM 600 hardware with VibroSight total condition monitoring software from the Vibro-Meter product line. Where piezoelectric velocity sensors are installed, this velocity sensor is a drop-in replacement including form, fit, function, wiring, and performance. The existing mounting and cabling can even be re-used if they are in good condition. The PV 102 has a lower noise floor to better resolve low vibration signals. The sensor is also tuned for band-pass flatness for improved repeatability. Its sensitivity is more stable with changing temperature, compared to previously-available velocity sensors. The sensor is the only velocity sensor of its kind to use 316L stainless steel with true hermetic sealing verified by helium leak testing. This design experience has resulted in a compression design that is superior to an out-dated shear design. The device is inherently more reliable as it has fewer components than typical piezoelectric velocity sensors and a simpler design. Additionally, sub-base isolation improves base strain sensitivity, minimizes the influence of mounting on sensor data, and protects against damaging electrostatic discharge. The device electronics are isolated from the sensor case for higher immunity against RF interference. The PV 102 is shipped with both 1/4-28 to 1/4-28 and1/4-28 to M8 mounting studs, to meet the needs of US and international customers. Other mounting options such as a 1/4-28 to M6 stud, cement mounting pads, and isolator mounting pads which electrically isolate the sensor from the machine it is monitoring to protect against high voltage spikes are also available. Several standard cable assemblies with MIL-C-5015 style sensor connectors and Teflon shielded, twisted pair cable are also provided. Customers can choose armoured or non-armoured cable; between a foil shield with IP67 rating at the connector and a braided shield with IP68 rating at the connector; and standard or custom lengths to suit their application. Enclosures including switch and termination boxes are also available. A complete condition monitoring and protection system is available, from the sensor to the user interface.