Showing papers on "Condition monitoring published in 1984"

The condition monitoring of rolling element bearings using vibration analysis

Abstract: A brief review on techniques of machine condition monitoring is presented followed by a description and results of a study involving the monitoring of vibration signatures of several rolling element bearings with a view to detecting incipient failure. The vibration data were analyzed and several parameters were assessed with regard to their effectiveness in the detection of bearing condition. It was found that all the parameters were of some value depending on the type of bearing failure encountered. Generally, frequency domain parameters were more consistent in the detection of damage than time domain parameters. However, sufficient evidence is produced to show that it would be unreliable to depend exclusively on any one technique to detect bearing damage.

A splicing and inspection technique for single-mode fibers using direct core monitoring

Abstract: A basic study has been made of single-mode fiber splicing techniques using direct core monitoring, which includes a highly accurate axis alignment and a post-inspection technique to guarantee the splice-loss standards. The standard conformance reliability, taking into account the core detection uncertainty, was studied by statistical theory. A method for setting acceptance criteria and necessary core detection accuracy has been established. Splice loss due to parameter mismatch, which cannot be estimated by core monitoring, was also examined.

Condition Monitoring of Machinery Using Computerized Vibration Signature Analysis

Abstract: Condition monitoring programs offer an innovative means for modern rotating equipment plants to implement and schedule predictive maintenance as opposed to relying on conventional preventive maintenance techniques. Although careful consideration is required during initial program planning and selection, these programs offer great flexibility since they may be designed for basic, Intermediate, or advanced needs. In addition a variety of monitoring methods may be incorporated in a program, ranging from basic sensing techniques to sophisticated hardwired computer stems. A viable condition monitoring program provides industry with a practical and cost-effective solution to the dilemma of accurately scheduling plant maintenance and coredly diagnosing heavy machinery problems.

Applications of Vibration Analysis to the Condition Monitoring of Rolling Element Bearings

Abstract: : Condition monitoring methods for rolling element bearings, which utilize the high frequency vibrations generated by bearing damage, have been investigated and compared experimentally. Kurtosis values, spectra of vibration signal envelopes and pulse measurement methods provided effective detection of early damage, but kurtosis in particular was not effective in evaluating extensive damage, where a combination of methods is required. Comparison of different accelerometer types used as vibration sensors gave very similar results, but an acoustic emission transducer provided indications of incipient damage significantly earlier than the accelerometers. Test were conducted under reasonably favourable conditions of measurement so further testing under less favourable conditions is proposed, and the effect of such conditions is briefly considered. Additional keywords: Australia; vibration meters; wear; antifriction bearings; charts. (Author)

Electrical condition monitoring of electric motors

Abstract: Methods and apparatus for monitoring the condition of an electrically driven motor by sampling one line quantity to the motor, typically current (I), calculating statistical moments, such as mean, standard deviation, skew or kurtosis, from a number of the sampled waveforms (18), comparing the calculated values with reference values (20) for a motor in good condition and applying significance testing (19) to the comparison. The motor condition can thus be monitored automatically and without the need for visual comparison of "current" waveform spectra. This procedure can follow pulse height analysis (16) and Fourier analysis (12), in which latter case (13) corresponds to (18) in the former case and (14, 15) correspond to (19, 20), the results being displayed at (25).

An efficient scheme for monitoring sensory conditions in robot systems

Abstract: An important use of sensing in robot systems is to initiate or terminate motions. The conditions for these actions are based on sensor data and thus called sensory conditions. The values of the sensor input may vary while the robot is moving or the environment is changing. Hence, the sensor data must be collected repetitively to support the updated evaluation of sensory conditions. In this paper, an efficient scheme for monitoring sensory conditions is presented. An auxiliary sensory processor is used to collect all sensor data (except the vision input) and monitor sensory conditions. Only the raw values of the sensor input will be checked to speed up the monitoring process. The threshold values of the raw data for matching sensory conditions are predetermined in the host computer and stored as a checking list in the sensory processor. The details of this scheme for different cases of sensory conditions are discussed. No floating point capability is needed for the sensory processor.

Reusable Rocket Engine Turbopump Condition Monitoring

Abstract: Significant improvements in engine readiness with attendant reductions in maintenance costs and turnaround times can be achieved with an engine condition monitoring system (CMS). The CMS provides real time health status of critical engine components, without disassembly, through component monitoring with advanced sensor technologies. Three technologies were selected to monitor the rotor bearings and turbine blades: the isotope wear detector and fiber optic deflectometer (bearings), and the fiber optic pyrometer (blades). Signal processing algorithms were evaluated and ranked for their utility in providing useful component health data to unskilled maintenance personnel. Design modifications to current configuration Space Shuttle Main Engine (SSME) high pressure turbopumps and the MK48-F turbopump were developed to incorporate the sensors.

A modern condition monitoring and gas turbine control system

Abstract: For plants with multiple gas turbines, a second generation integrated plant condition monitoring and control system combines prime mover and driven load controls with process controls for the balance of plant. Projected applications include electric power generation, cogeneration, combined cycle plants, and gas compression plants. The system offers redundant distributed control, with diagnostics, repair, and return to original fault tolerance levels. This forms the basis for projections of high control availability. Two data highways drastically reduce plant wiring while improving availability of communications. Color graphic plots of any parameter can be displayed, along with analysis of the condition of the plant components. The system can interface with dispatching telemetery systems.Copyright © 1984 by ASME

Machinery condition monitoring program, phase 4

Abstract: Ferrographic oil analysis, as applied to a shipboard maintenance management program, is described. Ferrographic oil analysis has predicted three documented engine failures and identifications of three sub-optimal operating conditions within diesel engines through identification of wear particles, particle composition and physical property testing of oil. The wear trending procedure is considered to be reliable. Results obtained from both laboratory and vessel test equipment are analyzed to identify repeatability of equipment. Linear regression analysis and discriminant analysis are applied to sample data to determine wear trends and assist in prediction of failures.

Condition Monitoring in the CEGB—Some Future Requirements for Tribology Related Problems

Abstract: This paper attempts to take a broad look at the practice and prospects for condition monitoring in the CEGB. The strategy of on-condition maintenance is compared with the current maintenance policy in the Board and it is concluded that, apart from auxiliary plant, there is no clear economic case for an on-condition approach. It is suggested that a rational approach to condition monitoring can only be achieved with a knowledge of plant failure statistics and the detailed characteristics of the failure modes. A detailed survey of plant failures is given with the specific examples of a tribological nature where the monitoring derived from knowledge of the failure mechanism. A brief review of the available monitoring techniques, benefits and shortcomings, and how these can be applied to the problems discussed is also given.