Determining an additional diagnostic parameter for improving the accuracy of assessment of the condition of stator windings in an induction motor

This paper has proposed and substantiated the application of an additional diagnostic parameter for assessing the state of stator windings of induction motors during operation. The dependences of the values of phase shifts between phase currents and phase voltages have been obtained. These dependences showed that when an inter-turn short circuit occurs in the stator windings, the phase shifts are the same for all phases of the motor. That has made it possible to obtain the dependence of the change in phase shift on the change in the engine shaft rotation frequency. This study's result has established the dependence of the rates of change of the phase angle on the engine shaft rotation frequency for both one and two damaged phases with varying degrees of damage. When analyzing these dependences, it was found that with an increase in the number of damaged phases of the electric motor, the linear section of the dependences decreases. In addition, with an increase in the degree of phase damage, the angle of inclination of the linear sections of the characteristics decreases. That has made it possible to determine an additional parameter for diagnosing the place and degree of an inter-turn short circuit of the windings in an induction motor with a squirrel-cage rotor. The values of the additional parameter, termed by this paper's authors as a "phase criterion" can be used to assess the condition and degree of damage to the stator winding of induction motors. The values of the phase criteria for various types of damage were: when phase A is damaged by 90 %, ξ=0.634, (deg)2/(rpm)2; when phase A is damaged by 80 %, ξ=0.393, (deg)2/(rpm)2; when phase A is damaged by 80 % and phase B is damaged by 90 %, ξ=0.25, (deg)2/(rpm)2; when phase A is damaged by 80 % and phase B is damaged by 90 %, ξ=0.173, (deg)2/(rpm)2. The results of this research could be used to select an effective method for diagnosing an inter-turn short circuit in the stator winding when building a diagnostic system for induction motors as part of drives of transport equipment

Immune complexes in blood serum of calves with clinical symptoms of bronchopneumonia

Pneumonia in preruminant calves is a multifactorial disease. Infectious agents, the environment, management and the immune status of the calves are all important factors in determining the outcome of an infection. Until today, the level and composition of circulating immune complexes in preruminant calves with pneumonia have not been studied in detail. We performed this work with the aim to determine whether pneumonia in three-month-old calves is followed by changes in the immune complex level and changes in the ?-globulin level as their possible constituents. Immune complexes from the calves? sera were isolated by polyethylene glycol (PEG) precipitation methods. Optical density at 350 nm (OD350) of redissolved precipitates was measured to determine the circulating immune complexes level. The OD350 level of PEG precipitates of calves with pneumonia at the time of diagnosis was 0.577?0.206 and it was statistically significantly higher (p<0.001) than OD350 the level of PEG precipitates of healthy calves (0.286?0.080). Electrophoretic analysis of sera and PEG precipitates showed that both slow and fast ?-globulins are found among serum and immune-complexes' ?-globulins, but the concentration of fast ?-globulins was significantly lower in sera of diseased calves. The level of PEG precipitable immune complexes was not correlated with the concentration of serum and PEG precipitable g-globulins. The results of this study have shown that by relatively simple PEG precipitation assay it is possible to detect an increased level of circulating immune complexes in calves with pneumonia. This can be used as an additional diagnostic parameter for the detection and follow up of the disease.

Osmotic fragility of peripheral blood lymphocytes in chronic lymphatic leukemia and malignant lymphoma

The osmotic fragility (OF) of peripheral blood lymphocytes from patients with chronic lymphatic leukemia (CLL) and non-Hodgkin malignant lymphoma (ML) was investigated employing an automatic recording method and compared with that of lymphocytes from healthy subjects and from patients suffering from various non-neoplastic diseases. The curves from CLL and ML showed a pattern of increased lymphocyte OF compared with those of the two control groups, and the difference was statistically significant ( less than 0.001). In CLL the increase in OF was more pronounced than in ML, and the shape of the curve was different from that in the other groups. The employment of peripheral blood lymphocyte OF as an additional diagnostic parameter in the diagnosis of CLL and ML is suggested.

Osmotic fragility of peripheral blood lymphocytes in chronic lymphatic leukemia and malignant lymphoma

The osmotic fragility (OF) of peripheral blood lymphocytes from patients with chronic lymphatic leukemia (CLL) and non-Hodgkin malignant lymphoma (ML) was investigated employing an automatic recording method and compared with that of lymphocytes from healthy subjects and from patients suffering from various non-neoplastic diseases. The curves from CLL and ML showed a pattern of increased lymphocyte OF compared with those of the two control groups, and the difference was statistically significant ( less than 0.001). In CLL the increase in OF was more pronounced than in ML, and the shape of the curve was different from that in the other groups. The employment of peripheral blood lymphocyte OF as an additional diagnostic parameter in the diagnosis of CLL and ML is suggested.