Reducing Transient Vibrations due to Rotating Shafts

An approach is proposed for calculating the transient torque imbalance of rotating shafts in the diesel generators of autonomous power units. The maximum shear strain of the rotor shaft in the generator is assessed by the finite-element method.     

A Magnetorheological Transformer Controlled by a Rotating Magnetic Field

New approaches to optimization of the parameters of a magnetorheological transformer are considered. The influence of the vortex magnetic field on the sedimentation of magnetic particles in a magnetorheological fluid changing its viscosity under the influence of an alternating magnetic field is considered. It is shown that it is advisable besides one throttle channel to enter an additional channel between coaxial cylinders, controlled by the rotating vortex magnetic field. The analysis of the constructed mathematical model revealed that with increasing the frequency of the fundamental harmonic of the input vibration signal, there is a frequency modulation of the controlling magnetic field.     

Experimental analysis of the operability of a system to control the oscillations of a mechanical system with self-synchronizing vibration exciters

The article presents the results of an experimental test of the automatic system to control the adjustment and maintenance of resonance oscillations of a mechanical system. The oscillations of the mechanical system are excited under rotation of unbalanced rotors of two AC induction motors. The operation of the control system is based on the measurement of the phase shift between the oscillations of the mechanical system and the exciting force.     

The calculation of the spatial vibration isolation system of a solid body under transport vibration

A mathematical model of the spatial rod system of vibration isolation of a solid subjected to the joint action of a constant acceleration and vibration is considered. Coefficients of the suspension stiffness matrix are determined depending on the static equilibrium position of the vibration-isolated body, which is determined by the direction and modulus of the constant acceleration. It is shown that it is possible to obtain various dynamic properties of the suspension depending on qualifying standards. Vibration-protective properties of the suspension are determined.     

Oscillations of the mechanical system, excited by unbalanced rotor of induction motor

The fluctuations of the mechanical system excited by an unbalanced rotor of an asynchronous AC motor are considered. Driving electromagnetic torque takes into account the relationship between flux linkage and currents in the windings of the engine.     

On the rational dynamic modes of vibrating machines with an unbalanced vibration exciter of limited power

The aspects of choosing the design parameters of a vibrating machine made according to the scheme of a series two-mass vibrating system, as well as of the modes of its oscillations excited by two synchronously rotating unbalanced vibration exciters with a drive of limited power, are considered. The limitations on possible modes of oscillation excitation caused by taking the designed features of the vibration exciter into account are determined. At the specified masses and stiffnesses of a vibrating system, as well as for the specified parameters of oscillations of the actuating element, the rational values of the parameters of vibration exciter and the damping in the components of the vibrating system and dynamic modes, which are characterized by low expenditures of energy and a small dynamic effort transmitted to the foundation of the machine, are determined. The oscillation modes in which changing the mass of the actuating element leads to the smallest changes of the amplitudes of its oscillations are determined.     

Advantages of the New VKT-7 Heat Calculator

Development data are given for an energy-independent (battery-powered) calculator for heat meters for use in open and closed water-based heat supply. Technical characteristics are given together with uses and also methods of monitoring heat consumption conditions and data processing for abnormal situations.