Steady-state longitudinal vibrations of sectional,physically nonlinear plates

The artile deals with steady-state longitudinal vibrations of plates consisting of curvilinear rings placed one inside the other without interference, under the effect of a harmonic distorting load acting along the outer periphery. The rings are made from different isotropic materials that are physically nonlinear. The problem is solved by the method of successive approximations. In each approximation the sought functions are represented in the form of expansions with respect to a small parameter. Numerical investigations were carried out for plates consiting of two concentrically arranged circular rings.Translated from Problemy Prochnosti, No. 3, pp. 24–27, March, 1991.     

Substantiation of flow charts for reverse-osmosis desalting with the ion-exchange softening of sea water and permeate

The article has considered flow charts for the preparation of make-up water of boilers of low, medium, and high pressure (9.8 MPa) from the sea water based on reverse-osmosis desalination. We have proved the possibility of deep Na-cationic softening of permeate by their own concentrates of the desalination stage. Reliable prevention of calcium deposits on membranes is achieved by acidulation of the waters of the Black Sea and Na-(Mg-Na)-zeolite softening process of the Caspian Sea waters also with the use of the concentrate for regeneration of the cation-exchanger.     

Torsional oscillation of tapered rods under arbitrary lateral loading

We consider steady-state torsional oscillation of a tapered rod under the action of tangential forces, which are arbitrarily distributed over its lateral surface, and twisting moments applied to its ends. To solve this problem, we suggest a method based on the series expansion of the displacement function in a nondimensional parameter which depends on the characteristics of the material and the frequency of loading. We present computational investigations for particular cases of loading. Translated from Problemy Prochnosti, No. 3, pp. 62–68, May–June, 1998.     

Sorption-membrane technologies for preparing makeup water at coastal thermal power stations

Technologies of preparing makeup water for boilers are considered, central to which is combined use of ion-exchange and reverse-osmosis methods for treatment of seawater and ocean water. It is shown that the concentrate produced by reverse-osmosis plants can be used as preferred material for regenerating filters at the stages during which source water and water at the outlet from the reverse-osmosis plant are treated with Na-and Mg-Na-cation exchange resins.     

The temperature effect on the performance of a traction asynchronous motor

The faults and damages of the asynchronous motors currently used in the traction rolling stock are reviewed. It is shown that a significant number of failures in operation are due to the excessive temperature in the stator coil and how it affects the mechanical characteristics and the traction performance of the asynchronous motor windings.     

Induction motor drives with minimal power losses

The goal is to synthesize a control system for an induction motor such as to ensure operation with minimal power losses. Standard nonlinearity and losses in the steel of the motor’s stator are taken into account in MatLab simulation. The proposed control system reduces the losses by up to 25% in comparison with classical scalar control.     

A simplified equivalent thermal circuit for the substitution of a stator in an induction motor

Based on a review of investigations of the thermal behavior of induction motors, it has been established that the stator winding of an induction motor is subject to very high values of temperature in most applications and work regimes. The analysis of techniques to determine the temperatures of different units of an induction motor helped us to propose the use of equivalent thermal circuits, in particular, a simplified substitution circuit for the determination of winding and a magnetic conductor of a stator. The thermal equilibrium equations were found. A technique to calculate the thermal resistances of a stator by means of a laboratory setup was developed. The setup considers the features of cooling specific types of motors; thus, it is unnecessary to observe an induction motor as an aerodynamic system. The technique was tested using a setup containing a 14-kW short-circuited induction motor. The temperatures in different units of a motor were measured using chromel–copel thermocouples, and its load simulated the load of a traction electric drive of transport vehicles. The results of the experimental investigation are presented to show the influence of the rotor speed and the cooling air flow on the thermal resistances.