scholarly journals Distribution Grid Stability—Influence of Inertia Moment of Synchronous Machines

2020 ◽  
Vol 10 (24) ◽  
pp. 9075
Author(s):  
Tomáš Petrík ◽  
Milan Daneček ◽  
Ivan Uhlíř ◽  
Vladislav Poulek ◽  
Martin Libra
Keyword(s):  
Synchronous Machine ◽  
Moment Of Inertia ◽  
Synchronous Machines ◽  
Frequency Variation ◽  
Distribution Grid ◽  
Inertia Moment ◽  
Moments Of Inertia ◽  
Frequency Grid ◽  
Load Angle

This paper shows the influence of grid frequency oscillations on synchronous machines coupled to masses with large moments of inertia and solves the maximum permissible value of a moment of inertia on the shaft of a synchronous machine in respect to the oscillation of grid frequency. Grid frequency variation causes a load angle to swing on the synchronous machines connected to the grid. This effect is particularly significant in microgrids. This article does not consider the effects of other components of the system, such as the effects of frequency, voltage, and power regulators.

Moments of inertia and B(E2;01+→21+)s in the NpNn scheme

2015 ◽  
Vol 93 (7) ◽  
pp. 711-715
Author(s):  
Rajesh Kumar ◽  
S. Sharma
Keyword(s):  
Nuclear Structure ◽  
Strong Dependence ◽  
Moment Of Inertia ◽  
Nucleon Pair ◽  
Valence Nucleon ◽  
Moments Of Inertia ◽  
Ground Band ◽  
Neutron Interaction ◽  
Medium Mass

We examine the collective nuclear structure of light and medium mass (Z = 50–82, N = 82–126) even–even nuclei using valence nucleon pair product (NpNn). We discuss the role of proton–neutron interaction in light mass nuclei and illustrate the variation of observables of collectivity and deformation (i.e., ground band moment of inertia) and B(E2) values with N and NpNn). The plot of these observables against NpNn vividly displays the formation of isotonic multiplets in quadrant I, strong dependence on NpNn in quadrant II and weak constancy with Z in quadrant III is illustrated.

New Theorems for Moments of Inertia

1993 ◽  
Vol 21 (4) ◽  
pp. 355-366 ◽  
Author(s):  
David L. Wallach
Keyword(s):  
Regular Polygon ◽  
Moment Of Inertia ◽  
Regular Polygons ◽  
Centre Of Mass ◽  
Moments Of Inertia ◽  
The Moment

The moment of inertia of a plane lamina about any axis not in this plane can be easily calculated if the moments of inertia about two mutually perpendicular axes in the plane are known. Then one can conclude that the moments of inertia of regular polygons and polyhedra have symmetry about a line or point, respectively, about their centres of mass. Furthermore, the moment of inertia about the apex of a right pyramid with a regular polygon base is dependent only on the angle the axis makes with the altitude. From this last statement, the calculation of the centre of mass moments of inertia of polyhedra becomes very easy.

scholarly journals Torque characteristics of double-stator permanent magnet synchronous machines

2017 ◽  
Vol 66 (4) ◽  
pp. 815-828
Author(s):  
Chukwuemeka Chijioke Awah ◽  
Ogbonnaya Inya Okoro
Keyword(s):  
Comparative Study ◽  
Permanent Magnet ◽  
Magnetic Force ◽  
Fault Tolerant ◽  
Synchronous Machine ◽  
Synchronous Machines ◽  
Permanent Magnet Synchronous Machines ◽  
Rotor Position ◽  
Rotor Pole ◽  
Static Torque

Abstract The torque profile of a double-stator permanent magnet (PM) synchronous machine of 90 mm stator diameter having different rotor pole numbers as well as dual excitation is investigated in this paper. The analysis includes a comparative study of the machine’s torque and power-speed curves, static torque and inductance characteristics, losses and unbalanced magnetic force. The most promising flux-weakening potential is revealed in 13- and 7-rotor pole machines. Moreover, the machines having different rotor/stator (Nr/Ns) pole combinations of the form Nr = Ns ± 1 have balanced and symmetric static torque waveforms variation with the rotor position in contrast to the machines having Nr = Ns ± 2. Further, the inductance results of the analyzed machines reveal that the machines with odd rotor pole numbers have better fault-tolerant capability than their even rotor pole equivalents. A prototype of the developed double-stator machine having a 13-pole rotor is manufactured and tested for verification.

Increasing the Moment of Inertia of Crane Rails Torsional

2017 ◽  
Vol 865 ◽  
pp. 188-191
Author(s):  
Kirill Nezdanov ◽  
Igor Garkin ◽  
Nikolay Laskov
Keyword(s):  
Economic Benefits ◽  
Cross Sectional Area ◽  
Moment Of Inertia ◽  
High Moment ◽  
Operating Costs ◽  
Sectional Area ◽  
Cross Sectional ◽  
Moments Of Inertia ◽  
Section Profile ◽  
The Moment

This article is devoted to extreme increase in the moments of inertia of crane rails torsional strongly influence the endurance of crane girders. We investigate increase in moment of inertia of the rail under torsion with increasing thickness of the walls and shelves of thick-walled I-section profile in the square until its transformation into a square profile. It was found that the transformation of the profile of a monolithic solid square increases the moment of inertia of the torsion Jkr, cm4 to 3,1075 times and reaches its extreme. A cross-sectional area remains constant (const). Crane rails with a high moment of inertia for torsion provides significant economic benefits, and significantly reduces the operating costs of the enterprise.

Influence of Inertial Effect on Fluorescence Anisotropy

1987 ◽  
Vol 42 (2) ◽  
pp. 123-126
Author(s):  
Jerzy Grzywacz ◽  
Zygmunt Trumpakaj
Keyword(s):  
Recent Work ◽  
Satisfactory Agreement ◽  
Fluorescence Anisotropy ◽  
Memory Function ◽  
Moment Of Inertia ◽  
Inertial Effects ◽  
Relaxation Equation ◽  
Exponential Form ◽  
Moments Of Inertia ◽  
Fluorescent Molecule

The influence of inertial effects on the fluorescence anisotropy r is discussed.From recent work on the anisotropy of a prolate fluorescent molecule in a liquid solvent it is known that its estimated experimental moment of inertia is as much as about 3 orders of magnitude greater than that calculated from its geometry.In this paper, by using a non-exponential form of the memory function K (t) in the generalized relaxation equation for r (t), a satisfactory agreement between measured and calculated moments of inertia is obtained.

scholarly journals Moments of Inertia of SDIBs in A = 190 Mass Region using VMI Model

2020 ◽  
Vol 12 (2) ◽  
pp. 209-214
Author(s):  
P. Jain ◽  
A. Goel ◽  
S. K. Mandal
Keyword(s):  
Theoretical Model ◽  
Large Range ◽  
Mass Region ◽  
Band Head ◽  
Moment Of Inertia ◽  
Moments Of Inertia ◽  
Transition Energies ◽  
Variable Moment ◽  
Dynamic Moment

A lot of identical bands are known at present in the Normal Deformed (ND) region. In our study of the occurrence and properties of identical bands in Super-Deformed (SD) nuclei we first applied the modified Variable Moment of Inertia (VMI) model to extract the band-head spin of Super-Deformed bands. The calculated transition energies, level spins and dynamic moment of inertia are systematically examined. Then, in the framework of theoretical model several identical bands are identified. The kinematic and dynamic moment of inertia have been calculated for the six pairs of Super-Deformed Identical Bands (SDIBs) which was not reported earlier in the literature. Thus, the results are significant. In all the cases J(2) is significantly higher than J(1) over a large range of frequency.

The Inertial Effect in Rotational Fluorescence Depolarization

1992 ◽  
Vol 47 (9) ◽  
pp. 971-973 ◽  
Author(s):  
A. Kawski ◽  
P. Bojarski ◽  
A. Kubicki
Keyword(s):  
Empirical Equation ◽  
Molecular Geometry ◽  
Moment Of Inertia ◽  
Experimental Results ◽  
Inertial Effect ◽  
Fluorescence Depolarization ◽  
Moments Of Inertia ◽  
Low Viscosity ◽  
The Moment ◽  
Semi Empirical

Abstract The influence of the moment of inertia on the rotational fluorescence depolarization is discussed. Based on experimental results obtained for five luminescent compounds: 2,5-diphenyloxazole (PPO), 2,2'-p-phenylene-bis(5-phenyloxazole) (POPOP), p-bis[2-(5-α-naphthyloxazolyl)]-benzene (α-NOPON), 4-dimethylamino-ω-methylsulphonyl-trans-styrene (3a) in n-parafines at low viscosity (from 0.22 x 10-3 Pa • s to 0.993 x 10-3 Pa • s) and diphenylenestilbene (DPS) in different solvents, a semi-empirical equation is proposed, yielding moments of inertia that are only two to five times higher than those estimated from the molecular geometry

scholarly journals Synchronization of Two Non-Identical Coupled Exciters in a Non-Resonant Vibrating System of Linear Motion. Part I: Theoretical Analysis

2009 ◽  
Vol 16 (5) ◽  
pp. 505-515 ◽  
Author(s):  
Chunyu Zhao ◽  
Hongtao Zhu ◽  
Ruizi Wang ◽  
Bangchun Wen
Keyword(s):  
Zero Solution ◽  
Moment Of Inertia ◽  
Moments Of Inertia ◽  
Vibrating System ◽  
Frequency Capture ◽  
Synchronization Problem ◽  
Small Parameters ◽  
Existence And Stability ◽  
Synchronous Operation ◽  
The Stability

In this paper an analytical approach is proposed to study the feature of frequency capture of two non-identical coupled exciters in a non-resonant vibrating system. The electromagnetic torque of an induction motor in the quasi-steady-state operation is derived. With the introduction of two perturbation small parameters to average angular velocity of two exciters and their phase difference, we deduce the Equation of Frequency Capture by averaging two motion equations of two exciters over their average period. It converts the synchronization problem of two exciters into that of existence and stability of zero solution for the Equation of Frequency Capture. The conditions of implementing frequency capture and that of stabilizing synchronous operation of two motors have been derived. The concept of torque of frequency capture is proposed to physically explain the peculiarity of self-synchronization of the two exciters. An interesting conclusion is reached that the moments of inertia of the two exciters in the Equation of Frequency Capture reduce and there is a coupling moment of inertia between the two exciters. The reduction of moments of inertia and the coupling moment of inertia have an effect on the stability of synchronous operation.

Dynamic Response of the Double Loop DC Motor Control System with the Different Moment of Inertia

2011 ◽  
Vol 411 ◽  
pp. 250-254
Author(s):  
Feng Sun ◽  
Niu Wang ◽  
Guo Feng Zhang
Keyword(s):  
Motor Control ◽  
Control System ◽  
Dynamic Response ◽  
Dc Motor ◽  
Moment Of Inertia ◽  
Double Loop ◽  
Inertia Moment ◽  
Mathematical Relation ◽  
Dc Motor Control ◽  
Motor Control System

According to the relation of inertia moment and electromechanical time constant, dynamic structure and inertia moment of double loop DC motor control system is proposed. The effect of the moment of inertia on the dynamic response process of the double-loop DC control system is analyzed. In addition, the mathematical relation of the inertia moment and the rotation acceleration for the double-loop DC control system is discussed. Lastly, the effectiveness of the mathematical relation is verified through the experiment of the actual system.

Thermal effects on the figure of the Moon

1967 ◽  
Vol 296 (1446) ◽  
pp. 266-269 ◽  
Keyword(s):  
Thermal Effects ◽  
Hydrostatic Equilibrium ◽  
Moment Of Inertia ◽  
The Moon ◽  
Moments Of Inertia ◽  
The Earth ◽  
Principal Moments Of Inertia ◽  
Long Time ◽  
The Stability ◽  
Lunar Rotation

Before discussing its cause, one must be clear in exactly what respect the lunar figure deviates from the equilibrium one. This is necessary because there has been confusion over the question for a long time. It was known early that the Moon’s ellipsoid of inertia is triaxial and that the differences of the principal moments of inertia determined from observations are several times larger than the theoretical values corresponding to hydrostatic equilibrium. The stability of lunar rotation requires that the axis of least moment of inertia point approximately towards the Earth and the laws of Cassini show that it is really so.

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