Vibration: Training, transmitter, accelerometer, displacement sensor
-- Control Engineering, 5/6/2008
Measurement of vibration helps with design testing and monitoring of equipment health. Training can help with implementation of related new products to measure and analyze vibration and shock, and make best use of resulting information.Random vibration and shock test training scheduled in Orlando: A short course on practical vibration and shock testing, measurement, analysis and calibration, and also HALT, ESS, and HASS, is scheduled Nov. 5-7, 2008, at Sypris Test & Measurement in Orlando, FL. The course will be taught by Wayne Tustin, internationally recognized vibration and shock educator, and president of Equipment Reliability Institute (ERI). People conducting vibration and shock tests, ESS, HALT, and HASS often lack formal training in this specialized area of mechanical engineering and may not understand why certain steps are necessary, says ERI, adding that nothing comparable is offered by university engineering departments. The ERI course is designed for engineers and technicians who conduct developmental and production vibration and shock tests, as well as for designers of products that must survive tests and rigorous service conditions. It also is said to benefit metrologists who measure vibration and shock on automobiles and aircraft, plus sales and applications engineers involved in sales of equipment used in test (shakers, shock test machines) and measurement (transducers, data acquisition). Equipment Reliability Institute is based in Santa Barbara, CA.
introduced the CSI 9330 Vibration Transmitter to continuously monitor critical rotating machinery for early detection of developing mechanical issues.
CSI 9330 is the latest in Emerson’s line of vibration transmitters which include multi-sensor and wireless capabilities.
The CSI 9330 is the latest in Emerson’s line of vibration transmitters which include multi-sensor as well as wireless capabilities. It can be deployed on any asset, but is typically installed on motor-fan, motor-pump, motor-compressor and cooling tower applications.
Once installed, it converts the analog output of an accelerometer into a 4-20mA signal, proportional to monitored vibration, and also delivers measurements, which provide additional insight into the condition of rotating element bearings and gear boxes.
Endevco Corp. introduces Model 7287 crush sensor with performance certified to specifications for critical test applications, the latest in the company’s series of transducers for crash test and related applications.
The 7287 is used in applications where certified performance to a known specification for ZMO and sensitivity is required, such as on-vehicle locations including bumpers, fenders, doors, and trunk lids which are likely to be heavily damaged during test. Specified to “max” or “min” values of key parameters, the 7287 can predict error budgets. A “POP” calibration data sheet is provided with sensitivity, ZMO and full scale range information. Features include input voltage of 10 V dc; output sensitivity of 0.10 mV/g; full scale range of 2,000 g; frequency response of 4,000 Hz with resonant frequency of 20,000 Hz; a small, lightweight configuration for easy glue mounting; PVC-jacketed cable less than 2 mm in diameter for easy installation, and cable routing with shielding to preserve signal integrity. Three form factors are available for maximum flexibility, two with cable and one without cable.
“The new Model 7287 is designed and built based on our decades of experience in high-end transducers and crash testing,” said David Bucka, automotive market segment manager for Endevco. “That proven foundation provides the assurance that the sensor will perform when needed, and that the product will be built and delivered as requested.” Endevco Corp. is based in San Juan Capistrano, CA.
Wilcoxon Research introduces stand-alone 4-20 mA vibration displacement sensor, adding it to its PC420 Series of 4-20 mA vibration sensors. PC420D is the first IEPE displacement transducer and 4-20 mA vibration transmitter packaged as a single sensor. The sensor monitors rotating equipment and outputs a real time 4-20 mA signal proportional to the vibration level. By trending real time data, plant personnel can schedule preventative maintenance activities around planned downtime. The 4-20 mA output is determined by first measuring peak-to-peak vibration, then converting that level to a 4-20 mA signal. Because balance components tend to dominate the vibration spectrum when viewed in displacement units, the sensor can track the balance component of machines, one of the most sought after parameters, Wilcoxon said. Integrating the signal into an existing PLC, DCS, or SCADA system simplifies real-time health monitoring because vibration, formerly considered too complex, can now be trended in easily understood units of mils or millimeters of displacement.
Measuring displacement can unmask hidden problems and provide data in easily understood measurement units. Instead of converting to displacement after the measurement is taken, a common practice in diagnostic vibration monitoring systems which can introduce errors known as “ski slopes,” the PC420D integrates at the measurement point for the cleanest vibration data.
“Plant personnel want to know the amount of mils at which a machine is operating, because mils is a readily understood parameter,” said Tom Smith, vice president of sales and marketing at Wilcoxon Research. “Existing displacement-type sensors, such as eddy current probes that measure shaft position, do not determine the level of machine vibration so we designed a displacement sensor specifically to meet this need.”
PC420D is used for condition based monitoring and predictive maintenance of motors in the speed (frequency) range of 300 rpm to 60,000 rpm (5 Hz to 1,000 Hz). It can be used to monitor balance of plant instrumentation such as pump motors, blowers, fan motors, compressor motors, and machine tool drive motors to reduce failure rates in the field.
A variety of the sensors is available to suit individual monitoring needs. The 4-20 mA output can be proportional to acceleration or velocity, with the full scale value being equal to the root-mean-square (rms), peak, or Wilcoxon’s true peak level.
A white paper on displacement monitoring is available from Wilcoxon Research knowledge desk. Wilcoxon Research is based in Germantown, MD.
For related reading, see:
Sensors, robotics, vision: Seismic accelerometer, hands-on demos –Control Engineering News Desk Register here and scroll down to select your choice of eNewsletters free. Talkback
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