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Theoretical Study of Vibrocentrifugal Separation of Grain Mixtures on a Sieveless Seed-cleaning Machine Full text
2021
Adamchuk, Valerii | Bulgakov, Volodymyr | Gadzalo, Iaroslav | Ivanovs, Semjons | Stepanenko, Serhiy | Holovach, Ivan | Ihnatiev, Yevhen
The article presents an analysis of known developments on creation of sieve-less pneumatic vibration centrifuges separating devices and processes of separating seed mixtures into fractions according to the complex of physical and mechanical properties of components. Mechanistic and mathematical models for studying the movement of particles over the sieve-free surface of pneumatic vibration separators were developed, theoretical studies of movement of seed mixture components were conducted and the most acceptable pneumatic vibration centrifugation process was determined by likeness to the process occurring on the separating surface of pneumatic sorting tables. To achieve the greatest separation of particles on the complex of their physical and mechanical properties (density, geometric dimensions, aerodynamic properties of seeds) is possible with the same direction of oscillatory motion and rotation of the separating surface performing the rotation in the direction from a larger radius to a smaller radius of the surface, in the “fluidization” mode, i. e. i.e. with periodic separation of the lower particles of the layer from the separating surface at simultaneous blowing of the layer by an air stream.
Show more [+] Less [-]Fault Diagnosis of Low-Power Three-Phase Induction Motor Full text
2016
Gedzurs, Aleksejs
Fault Diagnosis of Low-Power Three-Phase Induction Motor Full text
2016
Gedzurs, Aleksejs
An Induction motor reliability survey at an egg processing plant shows that almost 50% of the total motor failures are fan induction motors. Visual investigations of the faulty fan motors show that the main cause of the induction motor failure is air gap eccentricity. In this study, experimental tests are performed on a 1.1kW three-phase induction motor to detect air gap eccentricity and overheating of the induction motor. Heating tests show that end shield housing temperature reaches 100°C with blocked air flow from the fan, which can reduce the lifespan of the bearing. Dimension measurements of the end shield housing show that the dimensions of both tested motors back-end shields are larger than ISO tolerance grade limit. It leads to a loose fit between the housing and bearing, causing air gap eccentricity. Also, both motor back end shield housing has an out-of-round condition leading to an unbalanced magnetic pull. To detect the air gap eccentricity caused by too loose of a fit between housing bore and bearing, current Park’s vector approach is used. To measure three phase current, Hall Effect current transducers, a digital oscilloscope is used and Matlab software to process the measurement data. Results show that Park’s vector approach can be used to detect the air gap eccentricity caused by too loose a fit between bearing and housing. Therefore, the Park’s vector approach can be used to diagnose air gap eccentricity and analyse the type of the air gap eccentricity.
Show more [+] Less [-]Fault diagnosis of low-power three-phase induction motor Full text
2016
Gedzurs, A., Latvia Univ. of Agriculture, Jelgava (Latvia). Faculty of Engineering
An induction motor reliability survey at an egg processing plant shows that almost 50% of the total motor failures are fan induction motors. Visual investigations of the faulty fan motors show that the main cause of the induction motor failure is air gap eccentricity. In this study, experimental tests are performed on a 1.1kW three-phase induction motor to detect air gap eccentricity and overheating of the induction motor. Heating tests show that end shield housing temperature reaches 100°C with blocked air flow from the fan, which can reduce the lifespan of the bearing. Dimension measurements of the end shield housing show that the dimensions of both tested motors back-end shields are larger than ISO tolerance grade limit. It leads to a loose fit between the housing and bearing, causing air gap eccentricity. Also, both motor back end shield housing has an out-of-round condition leading to an unbalanced magnetic pull. To detect the air gap eccentricity caused by too loose of a fit between housing bore and bearing, current Park’s vector approach is used. To measure three phase current, Hall Effect current transducers, a digital oscilloscope is used and Matlab software to process the measurement data. Results show that Park’s vector approach can be used to detect the air gap eccentricity caused by too loose a fit between bearing and housing. Therefore, the Park’s vector approach can be used to diagnose air gap eccentricity and analyse the type of the air gap eccentricity.
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