This document discusses condition monitoring of rotating machines. It covers various techniques for monitoring parameters like temperature, vibration, electrical signals and fluxes to detect faults in machines like motors and generators. Local temperature can be monitored using devices embedded in the insulation near hot parts like the winding or core. Vibration is commonly monitored at various frequencies to analyze faults in components. Electrical signals like current and flux are also monitored to detect issues in windings or rotors. Overall, condition monitoring aims to continuously evaluate equipment health and detect early-stage faults in machines.
This presentation is equipped with the basic concepts of Condition Monitoring. The methods and analysis, circumscribed by Condition Monitoring, are summarized with an addition of application in this presentation.
This presentation is equipped with the basic concepts of Condition Monitoring. The methods and analysis, circumscribed by Condition Monitoring, are summarized with an addition of application in this presentation.
A wide range of Condition monitoring techniques is available in the industries over the world and some have become standards in many industries.
The "standard" techniques are:
1.Vibration Analysis
2.Oil Analysis
3.Thermal Analysis
4.Ultrasound Analysis
Machinery Vibration Analysis and Maintenance Living Online
This practical workshop provides a detailed examination of the detection, location and diagnosis of faults in rotating and reciprocating machinery using vibration analysis. The basics and underlying physics of vibration signals are first examined. The acquisition and processing of signals is reviewed followed by a discussion of machinery fault diagnosis using vibration analysis, and rectifying the unidentified faults. The workshop is concluded by a review of the other techniques of predictive maintenance such as oil and particle analysis, ultrasound and infrared thermography. The latest approaches and equipment used together with current research techniques in vibration analysis are also highlighted in the workshop.
MORE INFORMATION: http://www.idc-online.com/content/practical-machinery-vibration-analysis-and-predictive-maintenance-11
Vibration analysis can provide very useful information about the status of the equipment and the nature and severity of the problem.
It is possible to use these information to plan all maintenance activities and minimize machine downtime.
Condition Monitoring – Cost comparison with and without CM – On-load testing and offload testing –Methods and instruments for CM – Temperature sensitive tapes – Pistol thermometers – wear-debris analysis
Evaluation of reactances and time constants of synchronous generatoreSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
A wide range of Condition monitoring techniques is available in the industries over the world and some have become standards in many industries.
The "standard" techniques are:
1.Vibration Analysis
2.Oil Analysis
3.Thermal Analysis
4.Ultrasound Analysis
Machinery Vibration Analysis and Maintenance Living Online
This practical workshop provides a detailed examination of the detection, location and diagnosis of faults in rotating and reciprocating machinery using vibration analysis. The basics and underlying physics of vibration signals are first examined. The acquisition and processing of signals is reviewed followed by a discussion of machinery fault diagnosis using vibration analysis, and rectifying the unidentified faults. The workshop is concluded by a review of the other techniques of predictive maintenance such as oil and particle analysis, ultrasound and infrared thermography. The latest approaches and equipment used together with current research techniques in vibration analysis are also highlighted in the workshop.
MORE INFORMATION: http://www.idc-online.com/content/practical-machinery-vibration-analysis-and-predictive-maintenance-11
Vibration analysis can provide very useful information about the status of the equipment and the nature and severity of the problem.
It is possible to use these information to plan all maintenance activities and minimize machine downtime.
Condition Monitoring – Cost comparison with and without CM – On-load testing and offload testing –Methods and instruments for CM – Temperature sensitive tapes – Pistol thermometers – wear-debris analysis
Evaluation of reactances and time constants of synchronous generatoreSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology
Remediation of Old Substations for Arc Flash hazardIJAPEJOURNAL
Arc Flash is much different from the conventional shock hazard in the sense that it doesn’t involve direct contact of human beings with the live or energized part. The arcing energy involves high temperature of up to or beyond 20000K. This paper presents a case study of arc flash hazard analysis carried out in older industrial plant and the technological and work procedure changes that can be incorporated to reduce the incident energy level and thus provide a safer environment for the working personnels in plant.
IJERA (International journal of Engineering Research and Applications) is International online, ... peer reviewed journal. For more detail or submit your article, please visit www.ijera.com
Acoustic emission condition monitoring an application for wind turbine fault ...eSAT Publishing House
IJRET : International Journal of Research in Engineering and Technology is an international peer reviewed, online journal published by eSAT Publishing House for the enhancement of research in various disciplines of Engineering and Technology. The aim and scope of the journal is to provide an academic medium and an important reference for the advancement and dissemination of research results that support high-level learning, teaching and research in the fields of Engineering and Technology. We bring together Scientists, Academician, Field Engineers, Scholars and Students of related fields of Engineering and Technology.
Acoustic emission condition monitoring an application for wind turbine fault...eSAT Journals
Abstract Low speed rotating machines which are the most critical components in drive train of wind turbines are often menaced by several technical and environmental defects. These factors contribute to mount the economic requirement for Health Monitoring and Condition Monitoring of the systems. When a defect is happened in such system result in reduced energy loss rates from related process and due to it Condition Monitoring techniques that detecting energy loss are very difficult if not possible to use. However, in the case of Acoustic Emission (AE)technique this issue is partly overcome and is well suited for detecting very small energy release rates. Acoustic Emission (AE) as a technique is more than 50 years old and in this new technology the sounds associated with the failure of materials were detected. Acoustic wave is a non-stationary signal which can discover elastic stress waves in a failure component, capable of online monitoring, and is very sensitive to the fault diagnosis. In this paper the history and background of discovering and developing AE is discussed, different ages of developing AE which include Age of Enlightenment (1950-1967), Golden Age of AE (1967-1980), Period of Transition (1980-Present). In the next section the application of AE condition monitoring in machinery process and various systems that applied AE technique in their health monitoring is discussed. In the end an experimental result is proposed by QUT test rig which an outer race bearing fault was simulated to depict the sensitivity of AE for detecting incipient faults in low speed high frequency machine. Index Terms: Low speed rotating machine, and Condition Monitoring Systems, Acoustic Emission (AE)
Wind turbines form complex nonlinear mechanical systems exposed to uncontrolled wind
profiles. This makes turbine controller design a challenging task. As such, control of wind energy
conversion systems (WECS) is difficult due to the lack of systematic methods to identify requisite
robust and sufficiently stable conditions, to guarantee performance. The problem becomes more
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LOW VOLTAGE RIDE - THROUGH CAPABILITY OF WIND FARMSEditor IJMTER
Nowadays wind turbines are generally required to offer ancillary services similar to those
provided by conventional generators. One of the most important services wind turbines must offer is
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grid codes. In this paper, FACTS solutions for fixed speed wind farms such as DVR (Dynamic
Voltage Restorer) are presented as well as classic control and crowbar solutions for variable speed
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http://sandymillin.wordpress.com/iateflwebinar2024
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Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
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3. Introduction
By condition monitoring we mean continuous evaluation of the health of plant
and equipment throughout its serviceable life.
Condition monitoring and protection are closely related functions. The approach
to the implementation of each is, however, quite different.
Condition monitoring can, in many cases, be extended to provide primary
protection, but its real function must always be to attempt to recognise the
development of faults at an early stage.
11-05-2014 3SIBABRATA PRADHAN
4. WHAT AND WHEN TO MONITOR
Larger electrical drives, which support generating, process or production plant if
a high margin of spare capacity exists, will benefit from monitoring, although
perhaps not continuous monitoring.
We can include induced and forced-draught boiler fan drives, boiler water feed
pump drives, and cooling water pump drives in power stations in this category.
It must be kept in mind, however, that successful monitoring can allow a big
reduction in the requirement for on-site spare capacity.
11-05-2014 4SIBABRATA PRADHAN
5. WHAT AND WHEN TO MONITOR
The parameters to be monitored are essentially those that will provide the
operator and maintainer with sufficient details to make informed decisions on
operation and maintenance scheduling, but which ensure security of plant
operation.
Traditionally quantities, such as line currents and voltages, coolant temperatures,
and bearing vibration levels, have been measured and will continue to be used.
Other specialist methods, involving the accurate measurement of rotational
speed, or the sensing of leakage fluxes, are being developed in order to monitor a
variety of fault conditions.
11-05-2014 5SIBABRATA PRADHAN
6. WHEN TO MONITOR
One should monitor when it is cost-effective to do so, or when there are over-
riding safety considerations to be observed. The assessment of cost-effectiveness
can be a relatively complex matter, but in general terms monitoring is worthwhile
when the net annual savings are increased by its use.
11-05-2014 6SIBABRATA PRADHAN
8. ROOT
CAUSES AND
FAILURE
MODES
Root causes:
Defective design or manufacture
Defective material or component
Defective installation
Defective maintenance or operation
Ambient conditions
Overspeed
Overload
Component failure
Excessive temperature
Winding over temperature
Bearing over temperature.
11-05-2014 8SIBABRATA PRADHAN
10. Stator winding insulation
Stator winding insulation is affected by all of the stresses: thermal, electrical,
environmental and mechanical; however, the extent to which these stresses in
normal operation will cause problems in the short- or long-term will depend on
factors such as the operating mode and type of ambient cooling conditions.
Deterioration may be like delamination and voids, slot discharge etc.
The principal stresses of concern on rotor windings are thermal and mechanical.
It may be induction motor rotor faults, turbine generator rotor winding faults,
rotor winding faults in dc machine.
11-05-2014 10SIBABRATA PRADHAN
14. Vibration Measurement
Used for monitoring of components
of Gear boxes, Shaft couplings
Bearing etc.
Methods:
Displacement Transducer (< 100Hz)
Velocity Transducer (100-1000Hz)
Acceleration Transducer (> 1000 Hz)
Displacement Transducer:
11-05-2014 14SHYAM KR. SINGH
15. Velocity Transducer
E = Blv
where,
ov is the velocity of magnet in axial
direction
oE is induced emf which is the measure
of vibration.
11-05-2014 15SHYAM KR. SINGH
16. Acceleration Transducer
When subjected to vibration mass held
against piezoelectric material exerts a
force upon it which is proportional to
the acceleration which produces
electric voltage proportionally.
11-05-2014 16SHYAM KR. SINGH
17. Electrical & Magnetic measurement
Electrical Quantities like (currents ,
voltages) are measured by CT s, PT s .
Magnetic Quantities like (flux) are
measured by Hall Sensors.
When current flows through the hall sensor
in direction perpendicular to applied
magnetic field then direction of motion of
electron is in direction mutually
perpendicular to both axes.
V=KIB/nq.
where, K/nq is hall constant of material.
11-05-2014 17SHYAM KR. SINGH
18. Chemical Monitoring
The insulating materials used in
electrical machines are complex
organic materials when degraded
by heat or electrical action,
produce a very large number of
chemical products in the gas,
liquid and solid states.
Methods Of Chemical
Monitoring:
Particulate Detection (Using Core
Monitor)
11-05-2014 18SHYAM KR. SINGH
19. Chemical Monitoring
Infrared Ananlysis
A beam of light is focused through a
film of used oil and the wavelengths
are then compared to light transmitted
through new oil of the same type. The
differences in readings provide
information with respect to the
degradation of the used oil
Image Processing
The image processing and computer
vision system reveals more information
in the form of quantitative data not
revealed by the human eye.
This technique is used to collect
quantitative information from wear
particle images
11-05-2014 19SHYAM KR. SINGH
21. Vibration monitoring
The principal sources of vibration in electrical machines are:
The response of the stator core to the attractive force developed magnetically between
rotor and stator
The dynamic behavior of the rotor in the bearings as the machines rotates
The response of the shaft bearings, supported by the machine structure and
foundations, to vibration transmitted from the rotor
The response of the stator end windings to the electromagnetic forces on the
conductors.
11-05-2014 21ROHIT KAUSHIK
22. Frequency responses of the machine
elements
Stator response
The forces acting on the stator core are the result of the interaction between the
air gap flux wave and the currents flowing in the windings embedded in the stator
slots.
The forces acting on the end winding are due to the interaction between the end
leakage flux and the winding currents. It is apparent, therefore, that the precise
nature of the applied force waves will be a function of the form of the current
distribution, and the geometry of the air gap and end regions.
The simplest method of calculating the flux wave form is to multiply the
magnetomotive force (MMF) distribution because of winding currents, by the
permeance of the air gap.
11-05-2014 22ROHIT KAUSHIK
23. Frequency
responses of
the machine
elements
Transverse forces are due to asymmetries in the
machine, while torsion is primarily due to the
driving torque; however, both may be affected by
electrical or mechanical faults in the machine itself
or electrical or mechanical system disturbances
outside the machine.
There will also be a coupling between torsional and
transverse effects due to the transfer function or
stiffness between these axes of the machine, so
torsional effects, like current faults in rotor and
stator windings, can cause transverse effects like
vibrations, and vice versa.
Rotor response
We now consider the motion
of a rotor in response to:
Transverse force excitation
Torsional torque excitation
11-05-2014 ROHIT KAUSHIK 23
24. Frequency responses of the machine
elements
Bearing response
Rotor vibration force is transmitted to the stator via the air gap magnetic field and
the bearings in parallel. It is therefore important to consider the response of the
bearings to that vibration force so that its effect is not confused with vibrations
generated by faults within the bearings themselves.
11-05-2014 24ROHIT KAUSHIK
25. Monitoring techniques
Overall level monitoring
This simple form of monitoring is the most commonly used technique but its efficiency is
limited. The measurement taken is simply the rms value of the vibration level on the stator side
of the machine over a selected bandwidth. The usual bandwidth is 0.01–1 kHz or 0.01–10 kHz
11-05-2014 25ROHIT KAUSHIK
27. Monitoring techniques
Shock pulse monitoring
The shock pulse method is used exclusively for rolling element bearings ,which deteriorate at the
moving surfaces, developing small pits or imperfections.
The interaction between such surfaces generates mechanical stress wave or shock pulses, in the
bearing material, propagating into the structure of the machine.
These shock pulses are at ultrasonic frequencies and can be detected by piezoelectric transducers
with a resonant frequency characteristic tuned to the expected frequency of the pulses, around 32
kHz. The condition of the bearing is assessed by defining a quantity known as the shock pulse
value (SPV), defined as
SPV=R/N²*F².
11-05-2014 27ROHIT KAUSHIK
28. Monitoring techniques
Shock pulse interpretation
Overall vibration level trend Shock pulse value trend Comments
Low and rising Remains low No bearing damage
Low and rising Low but rising at the same
rate as the overall vibration
level
Bearing damage likely
Low and rising High value but constant Damaged bearing but another
problem is causing the rising
vibration
11-05-2014 28ROHIT KAUSHIK
29. Current & Flux monitoring
Faults on either rotor or stator disrupt the radial and circumferential patterns of
flux in the machine causing changes to the power being fed to the machine,
which can be detected via its terminal quantities voltage, current and power
measured outside the machine to give an indication of its condition.
A) Generator stator winding fault detection- The most significant technique in
this area is on-line discharge detection, which is dealt in further slides.
B) Generator rotor faults detection-
Turn-to-turn faults in a generator rotor winding may lead to
local overheating and eventually to rotor earth faults. In
addition, the shorting of turns causes unequal heating of the
rotor leading to bending and an unbalanced pull, which
together cause increased vibration
11-05-2014 29ROHIT KAUSHIK
30. Current & Flux monitoring
A way of detecting them on-line ,is using a
stationary search coil fitted in the air gap of the
machine. The search coil, of diameter less than
the tooth-width of the rotor, is fixed to the
stator usually in the air gap, and detects either
the radial or circumferential component of
magnetic flux.
New techniques have been developed utilising
a digital storage oscilloscope connected to the
search coil to give an initial indication of the
development of an inter-turn fault. The purpose
is to identify any asymmetry in the MMF
waveform caused by shorted turns.
Photographs of typical search
coil installation in large
generators
11-05-2014 30ROHIT KAUSHIK
31. Motor rotor faults detection
Stator current monitoring for rotor
faults
Any rotor fault in an induction
motor will cause a characteristic
swing in the supply ammeter
reading, Careful measurement of
the stator current will therefore
enable such a fault to be
monitored.
Detecting side bands in the supply current of
an induction motor
11-05-2014 31ROHIT KAUSHIK
32. Generator and motor comprehensive
methods
Shaft flux-
Shaft flux, or axial leakage flux, occurs in all electrical machines. It is
produced because no machine can be constructed with perfect symmetry.
Faults, such as winding short circuits, voltage imbalance and broken rotor
bars, represent severe disruptions to the internal symmetry of the machine. It
is logical to conclude, therefore, that the effect on the production of axial flux
will be readily observable.
11-05-2014 32ROHIT KAUSHIK
35. Temperature Monitoring
The limits to rating of electrical machines are generally set by the maximum
permissible temperature that the insulation can withstand.
There are three basic approaches to temperature monitoring.
• To measure local temperatures at points in the machine using embedded temperature detectors.
• To use a thermal image, fed with suitable variables, to monitor the temperature of what is
perceived to be the hottest spot in the machine.
• To measure the bulk temperatures of coolant fluids.
11-05-2014 35SAMRAT ROY
36. Local temperature measurement
This can be done using thermocouples, resistance temperature detectors or
embedded temperature detectors.
To monitor the active part of the machine they are usually embedded in:
• The stator winding and in the stator core.
• temperature detectors embedded in the stator winding need to be located close to its hottest part, which
may be in the slot portion or end-winding portion.
• The bearings to detect hot running.
11-05-2014 36SAMRAT ROY
38. Local temperature measurement
On a winding the devices have to
be embedded in the insulation at
some distance from the copper
itself.
11-05-2014 38SAMRAT ROY
39. Local temperature measurement
11-05-2014 39
As a result, the measured
temperature will not necessarily
be that of the winding itself but
an image of it.
SAMRAT ROY
40. Local temperature measurement
11-05-2014 40
The heat flow per unit area,
Q, through the insulation
system can be described by
simple conduction equations
as follows
𝑄 = ℎ 𝑇𝑠 − 𝑇𝑔 =
𝑘
𝑡2
𝑇𝑠 − 𝑇𝑡 =
𝑘
𝑡1
𝑇𝑐 − 𝑇𝑡
𝐸𝑙𝑖𝑚𝑖𝑛𝑎𝑡𝑖𝑛𝑔 𝑇𝑠
𝑇𝑡 = 𝑇𝑔 + 𝑄
𝑡2
𝑘
+
1
ℎ
SAMRAT ROY
42. Local temperature measurement
11-05-2014 42
So the measured temperature Tt will approach the temperature of the hottest
active component Tc if the thickness of insulation, t2 , applied over the ETD is
sufficient compared to the main insulation.
This problem does not occur for devices embedded in the slot portion between
two conductors, where there is a low heat flux between the active copper parts.
𝑇1~𝑇𝑐 𝑖𝑓 𝑇𝑔 ≪ 𝑇𝑐 &
𝑡2 +
𝑘
ℎ
𝑡1
≫ 1
SAMRAT ROY
43. Hot-spot measurement and thermal
images
11-05-2014 43
The thermal image technique has not received wide application on rotating elec-
trical machines.
The thermal image consists of a dial-type thermometer with its bulb immersed in
the region where the transformer oil is hottest.
A small heating coil, connected to the secondary of a current transformer, serves
to circulate around the bulb a current proportional to the load current and is such
that it increases the bulb temperature by an amount equal to the greatest winding-
to-coil temperature gradient.
SAMRAT ROY
46. Bulk measurement
11-05-2014 46
This can be found from the measurement of the internal and external coolant
temperature rises, obtained from thermocouples located.
This is done in most large machines
An increase in temperature rise would clearly show:
when a machine is being overloaded.
the coolant circuits are not performing as they should.
SAMRAT ROY
47. Conclusion
11-05-2014 47
Temperature measurement can yield very valuable bulk indications of the
condition of an electrical machine using
simple sensors
narrow bandwidth (<1 Hz)
low-data-rate signals
Temperature rises are important rather than absolute temperature.
There are advances in the application of modern sensors, which will allow temp-
erature measurements to be made closer to the active parts of a machine.
SAMRAT ROY
48. References:
[1]. P.TAVNER, L.RAN, J.PENMAN , H.SEDDING, ‘Condition Monitoring of Rotating
Electrical Machines’ 2008 – Book
[2]. TAVNER .P.J ‘ Review of condition monitoring of rotating electrical machines’, IET
Electric Power Applications, November 2007.
[3]. A. NEGOITA ,Gh. SCUTARU, R.M. IONESCU ‘A brief Review of Monitoring of
Rotating Electrical Machines ‘. Bulletin of the Transilvania University of Brasov • Vol. 3
(52) – 2010 Series I: Engineering Sciences.
[4]. NANDI S., TOLIYAT H.A., LI X.: ‘Condition monitoring and fault diagnosis of
electrical motors – a review’, IEEE Trans. Energy Convers., 2005, 20, (4), pp. 719–729.
[5]. TAVNER P.J., GAYDON B.G., WARD D.M.: ‘Monitoring generators and large motors’,
IEE Proc. B, Electr. Power Appl., 1986, 133, (3), pp. 169–180.
11-05-2014 48