Mounting hardware and accessoriesMounting considerations Surface Wilcoxons rugged sensors are designed to operate continuously in harsh industrial environments. Consideration of mount- ing surface and wiring requirements will ensure optimal performance of the sensor throughout the lifetime of the machinery being monitored. The accuracy of high frequency signals is dependent on how direct and rigid the contact is between the sensor and the machine. Adequately preparing the mounting surface provides the best performance and output of reliable data ensuring an accurate assessment of machine condition. Tips: Mount sensors in a location that minimizes the vibration transmission route from the driving point source of vibration (shaft) through the machine to the sensor Avoid mounting the sensor on thin sections, guards or vibration-free areas (antinodes), or areas with extreme temperature variations Use a silicon grease to increase the performance of permanently mounted sensors Frequency range The mounting location of each sensor should be based on the characteristics of the machinery to be monitored. The dynamic measurement requirements of frequency and amplitude range should be evaluated against the frequency range of the desired type of measurement. Each mounting method has a different effect on an sensors operating frequency range. Accelerometers have a natural resonance 3 to 5 times higher than the data sheet specified upper-end frequency response. The goal of measurement is to utilize the flat portion of the frequency response (the portion between the upper and lower 3 dB limit) for the best characterization of vibration levels. To ensure optimal response, careful attention should be made to the contact surface area and the proximity to the actual source of the vibration. 1 2 3 4 5 6 Curved Cementing Probe Flat surface Adhesive mounting Stud tip magnet magnet pad 500 -1,000 2,000 - 5,000 10,000- 30,000- Max sensor Frequency (Hz) 10,000 Hz Hz Hz 15,000 Hz 45,000 Hz response Acceptable Good Best Mounting options Permanent mounting: stud, cementing pad Stud mounting offers the widest and most accurate frequency dynamic measurement range and is highly recommended for permanent monitoring systems, high frequency testing such as gearbox monitoring and harsh environments. Cementing pads approach the high frequency capabilities of stud mounts when used properly, without the need of drilling into the structure. They are often used in applications where multiple locations will be measured using a single sensor. Mounting pads can also be used when multiple sensors are mounted for short periods of time, and directly epoxying the sensor is not practical. Adhesive mounting If the machine cannot be drilled or surface quality is poor, adhesives provide a secure attachment and are the next best alternative to epoxied mounting. The sensors operational frequency range will be reduced because the adhesive acts as a shock absorber, introducing a lower resonance than stud mounting. Replacement or removal of adhesive mounted sensors is the most difficult compared to any other mounting method. Temporary mounting: magnets and probe tips Magnets and probe tips used with sensors and data collectors are best when be used for walkaround monitoring programs. The frequency range of both methods is dramatically reduced compared to stud or adhesive mounts, but is still adequate for general purpose machine monitoring. Care must be used when interpreting data to account for resonance from mounting. Relative sensitivity (dB) Freqency range
