1. The document discusses vibration dampers and methods for reducing vibration. It describes various applications of dampers including ceiling dampers, tuned mass dampers, and addressing vibration in variable speed machines.
2. Analysis methods are presented for designing undamped and damped vibration absorbers using a two-degree-of-freedom system model. The absorber tuning required to reduce vibration amplitudes to zero is defined.
3. Various techniques are discussed for reducing vibration transmission and amplitude, including changing natural frequencies, adding damping, using isolation systems, active control methods, and vibration absorbers. Common vibration sources and effects are also mentioned.
Functions and Performance Requirements
Elements of an Excitation System
Types of Excitation Systems
Control and Protection Functions
Modeling of Excitation Systems
The functions of an excitation system are
to provide direct current to the synchronous generator field winding, and
to perform control and protective functions essential to the satisfactory operation of the power system
The performance requirements of the excitation system are determined by
Generator considerations:
supply and adjust field current as the generator output varies within its continuous capability
respond to transient disturbances with field forcing consistent with the generator short term capabilities:
rotor insulation failure due to high field voltage
rotor heating due to high field current
stator heating due to high VAR loading
heating due to excess flux (volts/Hz)
Power system considerations:
contribute to effective control of system voltage and improvement of system stability
Synchronous generator is a machine which converts mechanical power into electrical power. Three phase synchronous machine are used in thermal , hydro power plant to generate the electrical. Synchronous generator is used to generate the large number of electricity
Finite Element Analysis of the Beams Under Thermal LoadingMohammad Tawfik
A report on the finite element analysis of a beam under thermal loading. Nonlinear deflections and solution procedures covered.
#WikiCourses
https://wikicourses.wikispaces.com/TopicX+Nonlinear+Solid+Mechanics
https://eau-esa.wikispaces.com/Topic+Nonlinear+Solid+Mechanics
Mr. C.S.Satheesh, M.E.,
Time Response in systems
Time Response
Transient response
Steady-state response.
Delay Time (td)
Rise Time (tr)
Peak Time (tp)
Maximum Overshoot (Mp)
Settling Time (tS)
Standard Test Signals
Impulse signal
Step signal
Ramp signal
Parabolic signal
Motor Starter design for switchgears.
It contains Methods of induction motor starting include :
Direct on-line starting
Star-delta starting
Resistance stator starting
Autotransformer starting
Slip ring motor starting
Soft starter starting/slackening
Frequency converter starting
Device selection and proposed circuit for different motor powers and some definition about Load List and other technical consideration of design.
BLDC motor is the permanent magnet synchronous motor designed to have a trapezoidal back emf. Due to rugged construction, less control complexity, higher power density, variable speed over a wide range and flexibility to select the rotor construction suitable for particular application, it is being viewed as an alternative for conventional a.c. motors right from residential to commercial & aerospace systems. Rotation of BLDC motor is achieved by energizing the stator phases in a sequence, which depends on the rotor position. Hall sensors are used to detect the exact position of the rotor. This paper presents design of BLDC motor drive. For the purpose of demonstration, the popularly used loads are considered for industrial application, electric traction system.
Functions and Performance Requirements
Elements of an Excitation System
Types of Excitation Systems
Control and Protection Functions
Modeling of Excitation Systems
The functions of an excitation system are
to provide direct current to the synchronous generator field winding, and
to perform control and protective functions essential to the satisfactory operation of the power system
The performance requirements of the excitation system are determined by
Generator considerations:
supply and adjust field current as the generator output varies within its continuous capability
respond to transient disturbances with field forcing consistent with the generator short term capabilities:
rotor insulation failure due to high field voltage
rotor heating due to high field current
stator heating due to high VAR loading
heating due to excess flux (volts/Hz)
Power system considerations:
contribute to effective control of system voltage and improvement of system stability
Synchronous generator is a machine which converts mechanical power into electrical power. Three phase synchronous machine are used in thermal , hydro power plant to generate the electrical. Synchronous generator is used to generate the large number of electricity
Finite Element Analysis of the Beams Under Thermal LoadingMohammad Tawfik
A report on the finite element analysis of a beam under thermal loading. Nonlinear deflections and solution procedures covered.
#WikiCourses
https://wikicourses.wikispaces.com/TopicX+Nonlinear+Solid+Mechanics
https://eau-esa.wikispaces.com/Topic+Nonlinear+Solid+Mechanics
Mr. C.S.Satheesh, M.E.,
Time Response in systems
Time Response
Transient response
Steady-state response.
Delay Time (td)
Rise Time (tr)
Peak Time (tp)
Maximum Overshoot (Mp)
Settling Time (tS)
Standard Test Signals
Impulse signal
Step signal
Ramp signal
Parabolic signal
Motor Starter design for switchgears.
It contains Methods of induction motor starting include :
Direct on-line starting
Star-delta starting
Resistance stator starting
Autotransformer starting
Slip ring motor starting
Soft starter starting/slackening
Frequency converter starting
Device selection and proposed circuit for different motor powers and some definition about Load List and other technical consideration of design.
BLDC motor is the permanent magnet synchronous motor designed to have a trapezoidal back emf. Due to rugged construction, less control complexity, higher power density, variable speed over a wide range and flexibility to select the rotor construction suitable for particular application, it is being viewed as an alternative for conventional a.c. motors right from residential to commercial & aerospace systems. Rotation of BLDC motor is achieved by energizing the stator phases in a sequence, which depends on the rotor position. Hall sensors are used to detect the exact position of the rotor. This paper presents design of BLDC motor drive. For the purpose of demonstration, the popularly used loads are considered for industrial application, electric traction system.
Vibration suppression is considered as a keyresearch field in civil engineering to ensure the safety and comfort of their occupants and users of mechanical structures. To reduce the system vibration, an effective vibration control with isolation is necessary. Vibration control techniques have classically been categorized into two areas, passive and active controls. For a long time, efforts were made to make the suspension system work optimally by optimizing its parameters, but due to the intrinsic limitations of a passive suspension system, improvements were effective only in a certain frequency range. Compared with passive suspensions, active suspensions can improve the performance of the suspension system over a wide range of frequencies. Semi-active suspensions were proposed in the early 1970s [1], and can be nearly as effective as active suspensions. When the control system fails, the semi-active suspension can still work under passive condition
Dynamic analysis of machine foundation: when a static force cannot give the f...Gary Yung
This paper presents various design approaches for machine foundations from a rule of thumb static design to a comprehensive dynamic analysis and discusses their design limitations.
Vibration Analysis of an Automotive Silencer for Reduced Incidence of Failurepaperpublications3
Abstract: The Engine exhaust is the major source for contributing noise in automobile. There are many challenges in designing the muffler system as size, engine back pressure, noise level, emission norms and also cost. Sufficient insertion loss at engine frequency and first few harmonics are important. Recent efficient muffler systems are designed considering linear plane wave theory using transfer matrix method. Development of fibrous material strands that is used in hot exhaust system without binders has led to use of combination of muffler and exhaust system. Particulate matter filters and air cleaners also modified acoustically. For all these to happen exhaust muffler designers need simple and fast modeling tool, especially at the initial stages. FEM and Boundary element methods are time consuming. This paper is about plane wave based models such as transfer matrix method that has advantage of building fast prototype for muffler design, find out transmission loss and compared with experimental setup.
In this study Dynamic property of a structural element which is frequency, damping and mode shapes are described by a process called modal analysis. Structural condition can be monitored by analyzing the changes in frequencies and mode shapes. All materials posses certain amount of internal damping. Similarly steel fibers also produce some internal damping. A system is a combination of elements, for example a structure is a system whose elements are beams, columns, slabs, footings .etc. In all those elements I have selected beam elements. Many research works are conducted on different type of materials under dynamic loading.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
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NUMERICAL SIMULATIONS OF HEAT AND MASS TRANSFER IN CONDENSING HEAT EXCHANGERS...ssuser7dcef0
Power plants release a large amount of water vapor into the
atmosphere through the stack. The flue gas can be a potential
source for obtaining much needed cooling water for a power
plant. If a power plant could recover and reuse a portion of this
moisture, it could reduce its total cooling water intake
requirement. One of the most practical way to recover water
from flue gas is to use a condensing heat exchanger. The power
plant could also recover latent heat due to condensation as well
as sensible heat due to lowering the flue gas exit temperature.
Additionally, harmful acids released from the stack can be
reduced in a condensing heat exchanger by acid condensation. reduced in a condensing heat exchanger by acid condensation.
Condensation of vapors in flue gas is a complicated
phenomenon since heat and mass transfer of water vapor and
various acids simultaneously occur in the presence of noncondensable
gases such as nitrogen and oxygen. Design of a
condenser depends on the knowledge and understanding of the
heat and mass transfer processes. A computer program for
numerical simulations of water (H2O) and sulfuric acid (H2SO4)
condensation in a flue gas condensing heat exchanger was
developed using MATLAB. Governing equations based on
mass and energy balances for the system were derived to
predict variables such as flue gas exit temperature, cooling
water outlet temperature, mole fraction and condensation rates
of water and sulfuric acid vapors. The equations were solved
using an iterative solution technique with calculations of heat
and mass transfer coefficients and physical properties.
Harnessing WebAssembly for Real-time Stateless Streaming PipelinesChristina Lin
Traditionally, dealing with real-time data pipelines has involved significant overhead, even for straightforward tasks like data transformation or masking. However, in this talk, we’ll venture into the dynamic realm of WebAssembly (WASM) and discover how it can revolutionize the creation of stateless streaming pipelines within a Kafka (Redpanda) broker. These pipelines are adept at managing low-latency, high-data-volume scenarios.
Forklift Classes Overview by Intella PartsIntella Parts
Discover the different forklift classes and their specific applications. Learn how to choose the right forklift for your needs to ensure safety, efficiency, and compliance in your operations.
For more technical information, visit our website https://intellaparts.com
Hierarchical Digital Twin of a Naval Power SystemKerry Sado
A hierarchical digital twin of a Naval DC power system has been developed and experimentally verified. Similar to other state-of-the-art digital twins, this technology creates a digital replica of the physical system executed in real-time or faster, which can modify hardware controls. However, its advantage stems from distributing computational efforts by utilizing a hierarchical structure composed of lower-level digital twin blocks and a higher-level system digital twin. Each digital twin block is associated with a physical subsystem of the hardware and communicates with a singular system digital twin, which creates a system-level response. By extracting information from each level of the hierarchy, power system controls of the hardware were reconfigured autonomously. This hierarchical digital twin development offers several advantages over other digital twins, particularly in the field of naval power systems. The hierarchical structure allows for greater computational efficiency and scalability while the ability to autonomously reconfigure hardware controls offers increased flexibility and responsiveness. The hierarchical decomposition and models utilized were well aligned with the physical twin, as indicated by the maximum deviations between the developed digital twin hierarchy and the hardware.
Understanding Inductive Bias in Machine LearningSUTEJAS
This presentation explores the concept of inductive bias in machine learning. It explains how algorithms come with built-in assumptions and preferences that guide the learning process. You'll learn about the different types of inductive bias and how they can impact the performance and generalizability of machine learning models.
The presentation also covers the positive and negative aspects of inductive bias, along with strategies for mitigating potential drawbacks. We'll explore examples of how bias manifests in algorithms like neural networks and decision trees.
By understanding inductive bias, you can gain valuable insights into how machine learning models work and make informed decisions when building and deploying them.
Water billing management system project report.pdfKamal Acharya
Our project entitled “Water Billing Management System” aims is to generate Water bill with all the charges and penalty. Manual system that is employed is extremely laborious and quite inadequate. It only makes the process more difficult and hard.
The aim of our project is to develop a system that is meant to partially computerize the work performed in the Water Board like generating monthly Water bill, record of consuming unit of water, store record of the customer and previous unpaid record.
We used HTML/PHP as front end and MYSQL as back end for developing our project. HTML is primarily a visual design environment. We can create a android application by designing the form and that make up the user interface. Adding android application code to the form and the objects such as buttons and text boxes on them and adding any required support code in additional modular.
MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software. It is a stable ,reliable and the powerful solution with the advanced features and advantages which are as follows: Data Security.MySQL is free open source database that facilitates the effective management of the databases by connecting them to the software.
3. 3
1. Objectives
• Use vibration nomographs and vibration criteria to determine the leve
vibration to be controlled or reduced.
• Apply one- and two-plane balancing techniques for eliminating vibration
(unbalance).
• Control the vibration caused by the unbalance in rotating shafts.
• Reduce the unbalance in reciprocating engines.
• Design vibration and shock isolations for systems with fixed base as well
as vibrating base.
• Design active vibration-control systems.
• Design undamped and damped vibration absorbers
There are numerous sources of vibration in an industrial environment:
impact processes such as pile driving and blasting; rotating or reciprocating
machinery such as engines, compressors, and motors; transportation
vehicles such as trucks, trains, and aircraft; and the flow of fluids. The
presence of vibration often leads to excessive wear of bearings,
formation of cracks, loosening of fasteners, structural and mechanical
failures, frequent and costly maintenance of machines, electronic
malfunctions through fracture of solder joints, and abrasion of insulation
around electric conductors causing shorts. The occupational
1.OBJECTIVES
2. Introduction
4. 4
exposure of humans to vibration leads to pain, discomfort, and reduced
efficiency. Vibration can sometimes be eliminated on the basis of
theoretical analysis. However, the manufacturing costs involved in
eliminating the vibration may be too high; a designer must compromise
between an acceptable amount of vibration and a reasonable
manufacturing cost. In some cases the excitation or shaking force is
inherent in the machine. As seen earlier, even a relatively small excitation
force can cause an undesirably large response near resonance, especially
in lightly damped systems. In these cases, the magnitude of the
response can be significantly reduced by the use of isolators and auxiliary
mass absorbers
Material used in vibration dampers:
Metal, polymers, cement and their composites. Metal and polymer are dominant due
to their viscoelasticity. Damping enhancement mainly involves micro-structural
design for metals, interface design for polymers and admixture use for cement.
Metals:
• SMA’s
• Ferromagnetic alloys provide damping through magneto-mechanical
mechanism i.e. movement of magnetic domain in boundaries during vibration.
• Other alloys provide damping through micro-structural design. It is used due
to their low cost.
Polymers:
Due to their viscoelastic behavior, polymers (particularly thermoplastics) can
provide damping ability. Polymer used for damping rubber, polytetrafluoroethylene
(PTFE), polyurethane, polypropylene, polyvinylchloride, polyimide or other
polymer network. In general, elastomer and other amorphous thermoplastics with a
glass transition temperature below room temperature are attractive for damping.
Polymer blends and interpenetrating networks are also attractive, due to the interface
between the components in the blend or network providing a mechanism for
3. Dampers
5. 5
damping. In relation to fibrous structural composites, viscoelastic polymeric
interlayer's between the laminae of continuous fibers are often used for damping.
Sectional view of a monoblock shock absorber.
4.1 Ceiling Type
The Ceiling Vibration Absorber (G50T) can effectively reduce vibration and noise which
can cause interference to other neighboring rooms. Its triple vibration damping medium
structure ensures high performance results no matter where it is installed.
4. Applications
6. 6
4.2 Tuned mass damper
A tuned mass damper (TMD), also known as a harmonic absorber or seismic damper, is
a device mounted in structures to reduce the amplitude of mechanical vibrations. Their
application can prevent discomfort, damage, or outright structural failure. They are
frequently used in power transmission, automobiles, and buildings.
4.3 Variable Speed Machines
With the wide use of variable frequency drives in the pump industry and increasing unit
size, it is becoming more diffi cult to design mechanical systems free from natural
frequencies within operating speed range. If such an occurrence is allowed in the fi eld,
a resulting resonance condition threatens to signifi cantly impact performance and
longevity of the equipment. Traditional treatment methods that involve structural modifi
cations are often time consuming and expensive.
7. 7
When we attach an auxiliary mass m2 to a machine of mass m1 through a
spring of stiffness k2, the resulting two-degree-of-freedom system will look
as shown in Fig. The equations of motion of the masses m1 and m2 are
(1)
By assuming harmonic solution,
(2)
we can obtain the steady-state amplitudes of the masses m1 and m2 as
(3)
(4)
Undamped dynamic vibration absorber.
5. Analysis
8. 8
We are primarily interested in reducing the amplitude of the machine 1X12.
In order to make the amplitude of m1 zero, the numerator of Eq,should be
set equal to zero.
This gives
(5)
The machine operates near its resonance, before the addition
of the dynamic vibration absorber. Thus if the absorber is designed such
that
(6)
the amplitude of vibration of the machine, while operating at its original
resonant frequency,will be zero. By defining
(7)
as the natural frequency of the machine or main system, and
(8)
as the natural frequency of the absorber or auxiliary system, Eqs. and can
be rewritten as
10. 10
• Balancing of rotating machines—single- and two-plane balancing.
• Controlling the response and stability of rotating shafts.
• Balancing of reciprocating engines.
• Reducing vibration caused by impacts due to clearances in the joints of
machines and mechanisms.
The following methods are discussed to reduce transmission of vibration
from the source:
• Changing the natural frequency of the system when the forcing frequency
cannot be altered.
• Introducing a power-dissipation mechanism by adding dashpots or
viscoelastic materials.
6. Discussion
11. 11
• Designing an isolator which changes the stiffness/damping of the system.
• Using an active control technique.
• Designing a vibration absorber by adding an auxiliary mass to absorb the
vibration energy of the original mass.
1. Mechanical Vibrations Sixth Edition in sl Units SINGIRESU S.RAO
2. Engineering Vibrations Fourth Edition DANIEL J. INMAN
3. Mechanical Vibration Fourth Edition ANALYSIS,
UNCERTAINTTIES,AND CONTROL
7.References