Efficiency of VFD Coupled Induction Motors Operating in the Scalar Mode with Different Types of Loads

2019 ◽  
pp. 45-59
Author(s):  
L. Latchoomun ◽  
C. Gokhool ◽  
R. T. F. Ah King ◽  
K. Busawon ◽  
J. P. Barbot
Keyword(s):  
Induction Motors ◽  
Different Types ◽  
Scalar Mode

Voltage Instability of Initiation Fault Duration as Influenced by Nodes Short Circuit Levels NSCL with Different Types of Loads

2016 ◽  
Vol 6 (3) ◽  
pp. 1305 ◽  
Author(s):  
Youssef Ahmed Mobarak ◽  
Mahmoud M. Hussein
Keyword(s):  
Power System ◽  
Induction Motors ◽  
Short Circuit ◽  
Constant Current ◽  
Transmission Network ◽  
Voltage Instability ◽  
Different Types ◽  
Short Circuits ◽  
System Dynamic Simulation ◽  
Constant Impedance

The occurrence of voltage instabilities or voltage collapses depend on the duration of the persistence of the fault and on the type of fault, some faults lead to voltage instabilities, others lead to voltage collapse. Evaluation of fault durations causing occurrence of voltage instabilities is the main goal of this paper. This paper searches for the effect of nodes short circuit levels NSCL and its duration periods initiation of voltage instability, with lagging and leading load power factors at certain loads buses. In this paper, the power system dynamic simulation program is developed for dynamic analysis of voltage stability. This paper is concerned with the fault duration which lead to the occurrence of voltage instability phenomena due to NSCL. The fault which lead to voltage instability is found to be short circuits at certain nodes cleared without any variation in the transmission system elements, i.e. the post-fault conditions will be the same as the pre-fault conditions. Models for loads considered in this study are induction motors with three different shaft mechanical loads, constant impedance CZ loads, constant current CI loads and constant power CP loads are used, as they depict the behavior of most power system loads. The influence of the transmission network impedances, which are nearly the inverse of the NSCL, on the fault duration which lead to the occurrence of voltage instabilities are studied and evaluated using various load representations.<strong><em></em></strong>

scholarly journals Bearing Fault Detection in Induction Motors Using Line Currents

2021 ◽  
Vol 19 (2) ◽  
Author(s):  
Sunder M ◽  
Abishek R ◽  
Sabarivelan S ◽  
Monalisa Maiti ◽  
Kishore Bingi
Keyword(s):  
Numerical Analysis ◽  
Fault Detection ◽  
Induction Motors ◽  
Bearing Fault ◽  
Bearing Fault Detection ◽  
Detection Model ◽  
Proposed Model ◽  
Different Types ◽  
The Hilbert Transform ◽  
Vector Approach

This paper focuses on the development of a bearing fault detection model for induction motors using line currents. The graphical and numerical analysis of the model has been developed using the park's vector approach and envelope based on the Hilbert transform. The proposed model has been evaluated on currents measured from eight different types of induction motors. The graphical results from the Concordia pattern between d- and q-components of stator currents show that healthy bearing behaviour is circular compared to the faulty bearing's elliptical. The numerical results show that the minimum and maximum envelope of d- and q-components of stator currents is more significant than one. The sum of Kurtosis for the envelope of d- and q-components of stator currents is less than 5.0.

scholarly journals Voltage Instability of Initiation Fault Duration as Influenced by Nodes Short Circuit Levels NSCL with Different Types of Loads

2016 ◽  
Vol 6 (3) ◽  
pp. 1305 ◽  
Author(s):  
Youssef Ahmed Mobarak ◽  
Mahmoud M. Hussein
Keyword(s):  
Power System ◽  
Induction Motors ◽  
Short Circuit ◽  
Constant Current ◽  
Transmission Network ◽  
Voltage Instability ◽  
Different Types ◽  
Short Circuits ◽  
System Dynamic Simulation ◽  
Constant Impedance

The occurrence of voltage instabilities or voltage collapses depend on the duration of the persistence of the fault and on the type of fault, some faults lead to voltage instabilities, others lead to voltage collapse. Evaluation of fault durations causing occurrence of voltage instabilities is the main goal of this paper. This paper searches for the effect of nodes short circuit levels NSCL and its duration periods initiation of voltage instability, with lagging and leading load power factors at certain loads buses. In this paper, the power system dynamic simulation program is developed for dynamic analysis of voltage stability. This paper is concerned with the fault duration which lead to the occurrence of voltage instability phenomena due to NSCL. The fault which lead to voltage instability is found to be short circuits at certain nodes cleared without any variation in the transmission system elements, i.e. the post-fault conditions will be the same as the pre-fault conditions. Models for loads considered in this study are induction motors with three different shaft mechanical loads, constant impedance CZ loads, constant current CI loads and constant power CP loads are used, as they depict the behavior of most power system loads. The influence of the transmission network impedances, which are nearly the inverse of the NSCL, on the fault duration which lead to the occurrence of voltage instabilities are studied and evaluated using various load representations.<strong><em></em></strong>

Rotor fault detection in induction motors operated with different types of soft-starters

2020 ◽  
Author(s):  
M. Garcia-Pellicer ◽  
A. Quijano-Lopez ◽  
J.A. Antonino-Daviu ◽  
I. Higuero-Torres ◽  
E. Martinez-Montes ◽  
...  
Keyword(s):  
Fault Detection ◽  
Induction Motors ◽  
Different Types

The extinction time of a general birth and death process with catastrophes

1986 ◽  
Vol 23 (04) ◽  
pp. 851-858 ◽  
Author(s):  
P. J. Brockwell
Keyword(s):  
Laplace Transform ◽  
Size Distribution ◽  
Sufficient Conditions ◽  
Necessary And Sufficient Conditions ◽  
Death Process ◽  
Extinction Time ◽  
Birth And Death Process ◽  
Different Types ◽  
The Laplace Transform ◽  
Necessary And Sufficient

The Laplace transform of the extinction time is determined for a general birth and death process with arbitrary catastrophe rate and catastrophe size distribution. It is assumed only that the birth rates satisfyλ0= 0,λj&gt; 0 for eachj&gt; 0, and. Necessary and sufficient conditions for certain extinction of the population are derived. The results are applied to the linear birth and death process (λj=jλ, µj=jμ) with catastrophes of several different types.

Differentiating between different forms of moral obligations

2020 ◽  
Vol 43 ◽  
Author(s):  
Rajen A. Anderson ◽  
Benjamin C. Ruisch ◽  
David A. Pizarro
Keyword(s):  
Moral Character ◽  
Moral Obligations ◽  
Different Types

Abstract We argue that Tomasello's account overlooks important psychological distinctions between how humans judge different types of moral obligations, such as prescriptive obligations (i.e., what one should do) and proscriptive obligations (i.e., what one should not do). Specifically, evaluating these different types of obligations rests on different psychological inputs and has distinct downstream consequences for judgments of moral character.

Ultrastructural Investigations of the Contractile Filaments of Amoebae

1974 ◽  
Vol 32 ◽  
pp. 188-189
Author(s):  
P.L. Moore
Keyword(s):  
Cytoplasmic Streaming ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Amoeboid Movement ◽  
Different Types ◽  
Chemical Conditions ◽  
Complete Interpretation

Previous freeze fracture results on the intact giant, amoeba Chaos carolinensis indicated the presence of a fibrillar arrangement of filaments within the cytoplasm. A complete interpretation of the three dimensional ultrastructure of these structures, and their possible role in amoeboid movement was not possible, since comparable results could not be obtained with conventional fixation of intact amoebae. Progress in interpreting the freeze fracture images of amoebae required a more thorough understanding of the different types of filaments present in amoebae, and of the ways in which they could be organized while remaining functional.The recent development of a calcium sensitive, demembranated, amoeboid model of Chaos carolinensis has made it possible to achieve a better understanding of such functional arrangements of amoeboid filaments. In these models the motility of demembranated cytoplasm can be controlled in vitro, and the chemical conditions necessary for contractility, and cytoplasmic streaming can be investigated. It is clear from these studies that “fibrils” exist in amoeboid models, and that they are capable of contracting along their length under conditions similar to those which cause contraction in vertebrate muscles.

Study of the Molecular Architecture of Keratin Filaments by Electron Microscopy

1982 ◽  
Vol 40 ◽  
pp. 118-119
Author(s):  
U. Aebi ◽  
P. Rew ◽  
T.-T. Sun
Keyword(s):  
Electron Microscopy ◽  
Structural Organization ◽  
Cell Types ◽  
Structural Features ◽  
Molecular Architecture ◽  
The Past ◽  
Keratin Filaments ◽  
Different Types ◽  
10 Nm Filaments ◽  
Different Cell Types

Various types of intermediate-sized (10-nm) filaments have been found and described in many different cell types during the past few years. Despite the differences in the chemical composition among the different types of filaments, they all yield common structural features: they are usually up to several microns long and have a diameter of 7 to 10 nm; there is evidence that they are made of several 2 to 3.5 nm wide protofilaments which are helically wound around each other; the secondary structure of the polypeptides constituting the filaments is rich in ∞-helix. However a detailed description of their structural organization is lacking to date.

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