CALIFORNIA STATE UNIVERSITY, NORTHRIDGE
INDUCTION MOTOR FAULT DIAGNOSIS USING LABVIEW
A graduate project submitted in partial fulfillment of the requirements For the degree of Master of Science in Electrical Engineering
By
NagaLalitha Kurapati
December 2015 The graduate project of NagaLalitha Kurapati is approved:
Dr. Xiaojun Geng Date
Prof. Benjamin F. Mallard Date
Dr. Ruting Jia, Chair Date
California State University, Northridge
ii ACKNOWLEDGEMENT
Here I start my project paper with thankfulness to my parents, Mr. Jagan Mohan
Rao, Ms. NagaRaja Kumari who supported and blessed me to stand here.
I would like to express honor and thanks to my project chairperson and guide Dr.
Ruting Jia, Ph.D. Chair, who supported me and gave inspiration to achieve this task as part of my graduation program.
I would like to continue my thankfulness to my project committee member Dr.
Xiaojun (Ashley) Geng, PhD and Prof. Benjamin F. Mallard for their continuous support and guidance.
My special gratitude to my husband, Mani Popuri and all my friends for encouragement and support.
Nagalalitha Kurapati
iii TABLE OF CONTENTS
SIGNATURE PAGE ...... ii ACKNOWLEDGMENT………………………………………………...... iii LIST OF TABLES ...... vi LIST OF FIGURES...... vii ABSTRACT…………………………………………………………...... ix 1. INTRODUCTION 1.1 Overview....……………………………………………………………... 1 1.2 Single Phase Induction Motor ...... …………………………….…. 1 1.2.1 Working Principle ...... ………….…………………….... 2 1.2.2 The Split Phase Induction Motor ...... 3 1.2.3 Capacitor Start Induction Motor...... 3 1.2.4 Permanent- Split Capacitor Motor...... 4 1.2.5 Capacitor Start Capacitor Run Motor...... 4 1.2.6 Shaded Pole Induction Motor...... 5 1.2.7 Universal Motor...... 6 1.2.8 Synchros...... 6 1.2.9 DC Tachometer...... 7 1.2.10 AC Tachometer ...... 7 1.2.11 Two Phase Servo Motor...... 8 1.3 Three Phase Induction Motor...... 8 1.3.1 Working Principle...... 8 1.3.2 Squirrel Cage Induction Motor...... 9 1.3.3 Phase Wound Rotor ...... 10
2. DESIGN THEORY 2.1 Design...... 12 2.1.1 AC Waveform Generation...... 14 2.1.2 abc to qd Conversion...... 14 2.1.3 Q & D Axis Transformation ...... 14
iv 2.1.4 Rotor ...... 15 2.1.5 Inverse Transformation ...... 15 2.2 Park's Vector ...... 15
3. SIMULATIONS AND RESULTS 3.1 Introduction To Lab View...... 17 3.2 AC Waveform Generation ...... 17 3.3 abc to qd Conversion...... 20 3.4 Q & D Axis Transformation...... 21 3.5 Rotor ...... 23 3.6 Inverse Transformation...... 24 3.7 Integrated Block ...... 26 3.8 Results ...... 28 4. FUTURE SCOPE...... 33 5. CONCLUSION...... 34
REFERENCES ...... 35
v LIST OF TABLES
Table 1 - AC Waveform Generation...... 18 Table 2 - abc to qd Conversion ...... 21 Table 3 - Q & D Axis Transformation...... 22 Table 4 - Rotor...... 24 Table 5 - Inverse Transformation ...... 25
vi LIST OF FIGURES
Figure 1 - Single Phase Induction Motor...... 2 Figure 2 - Working Of Induction Motor In Single Phase ...... 2 Figure 3 - The Split Phase Induction Motor ...... 3 Figure 4 - Capacitor Start Induction Motor...... 4 Figure 5 - Permanent- Split Capacitor Motor ...... 4 Figure 6 - Capacitor Start Capacitor Run Motor...... 5 Figure 7 - Shaded Pole Induction Motor...... 5 Figure 8 - Universal Motor...... 6 Figure 9 - Synchros...... 6 Figure 10 - AC Tachometer ...... 7 Figure 11 - Two Phase Servo Motor ...... 8 Figure 12 - Working of Three Phase Induction Motor...... 9 Figure 13 - Squirrel Cage Induction Motor ...... 10 Figure 14 - Phase Wound Rotor...... 10 Figure 15 - Induction Motor Circuit Model...... 13 Figure 16 - Block Diagram In Fault Condition of AC Waveform Generation ...... 18 Figure 17 - Block Diagram In Healthy Condition of AC Waveform Generation ..... 19 Figure 18 - AC Waveform Front Panel ...... 20 Figure 19 - Block Diagram Of abc to dq Conversion ...... 20 Figure 20 - Front Panel for abc to dq Conversion ...... 21 Figure 21 - Front Panel for Q & D Transformation ...... 22 Figure 22 - Block Diagram Of Q & D Transformation ...... 23 Figure 23 - Block Diagram Of Torque And Speed ...... 23 Figure 24 - Front Panel for Torque And Speed ...... 24 Figure 25 - Block Diagram of Inverse Transform ...... 25 Figure 26 - Front Panel for Inverse Transform...... 26 Figure 27 - Block Diagram of Integrated Block ...... 27 Figure 28 - Front Panel for Integrated Block ...... 28 Figure 29 - Fault Condition With 110V ...... 29
vii Figure 30 - No Fault Condition With 110V...... 29 Figure 31 - Fault Condition With 220V ...... 30 Figure 32 - No Fault Condition With 220V ...... 30 Figure 33 - Fault Condition With 415V ...... 31 Figure 34 - No Fault Condition With 415V ...... 31
viii ABSTRACT
INDUCTION MOTOR FAULT DIAGNOSIS USING LABVIEW
BY NAGALALITHA KURAPATI
MASTER OF SCIENCE IN ELECTICAL ENGINEERING
In this fasting going world, mechanized industries of electrical machines are needy of an effortless and the untimely fault detection techniques as they are attire by the customers. However, many researchers have urbanized numerous fault diagnosing methods, comprehensible software with preset extensive measurement practice is needed so that the personnel who are not aware of the software can also work on this to recognize the faults occurred. In this paper an induction motor is constructed in a stationary reference for handiness. Faulty conditions are incorporated in the replica to evaluate the consequence of fault in the motor using the software, Lab VIEW.
ix CHAPTER 1. INTRODUCTION
1.1 Overview The induction motor is healthy suitable for relevancies needed steady rate function. Commonly, the induction motors are economical and trouble free to maintain compare to other kind of motors. The induction motors are through up of the rotator and stator windings.
The stator holds a series of wire windings attached to motor which are small resistance and joined to motor frame. Whenever voltage and current is efficient to the stator winding which is surrounded to motor workstation, then the magnetism generates through these windings [1].
The stator windings are arranged with a technique, to generate a field of magnetism power to spin synchronously inside the motor. Rotor encompasses a quality of thin bars, accumulated in a coated cylinder.
These prearranged bars are almost parallel and straight to the shaft in the rotor. The end of the sides of the motor these bars are mutually coupled by means of a shortening ring. The stator and rotor are divided by an air gap which permits to the movement of a rotor.
1.2 Single Phase Induction Motor The most used induction motors today are single phase induction motors. These AC motors are least pricey and entails low safeguarding. This type of motors exploits a succinct type of wires on a framework and accomplishes the currents from the torque as shown in the figure 1. This current move in form of loops through changing the field of magnetism generated in stationary twirls. This induction motor is secret depending on the technique of starting.
1
Figure 1 - Single Phase Induction Motor [1]
1.2.1 Working Principle Motor to rotate, two fluxes are required so that the torque is produced which will cause the motor to rotate. After the a.c. source is set to stator, the alternative current flows and alternative flux is generated by this alternative current. The emf gets stimulated in a rotor. The flux cuts rotor conductors. There are two fluxes, stator and rotor which are produced by stator and rotor currents respectively. As the flux is generated due to induction, the motor is called the induction motor which is shown in figure 2. The stator and rotor flux causes the torque that makes the motor to rotate [1].
Figure 2 - Working Of Induction Motor In Single Phase [2]
2 1.2.2 The Split phase Induction motor
There are many kinds of self, starting motors, well-known as split phase motors. These types of motors have an initial winding relocate 90 o electrical commencing the major or running winding as shown in figure 3. In a few categories, the initial winding has quite high resistance, which causes the current to be out of a phase through the current in the operating winding. This circumstance creates a rotating field and the rotor revolves. A centrifugal switch detaches the initial winding mechanically, after the rotor has attained just about 25 percent of its rated speed.
Figure 3 -The Split Phase Induction Motor [1]
1.2.3 Capacitor Start Induction Motor
By means of improvement of high competence electrolytic capacitors, a difference of the split phase motor, known as the capacitor start motor, has been prepared. In this version, the initial winding and running winding have the akin size and resistance value which is shown in figure 4. The phase shift stuck among the currents of the windings is attained by means of capacitors coupled in a series by means of the initial winding.
A Capacitor start induction motors have a starting torque equivalent to their torque at rated speed. A centrifugal switch is essential for separating the initial winding when the rotor speed is just about 25 percent of the rated speed.
3
Figure 4 - Capacitor Start Induction Motor [1]
1.2.4 Permanent - Split Capacitor Motor
This motor assembly is simplified by not having the switch because after starting the motor, the capacitor and auxiliary winding is not detached. The backward rotating magnetic field exclusion can be achieved in this motor as the capacitor and the auxiliary winding can be designed so that the permanent - split capacitor motor works as a 2-phase at any preferred load as shown in the figure 5. Split motor is a noise free motor. This motor is very efficient kind of motor [1].
Figure 5 - Permanent - Split Capacitor Motor [1]
1.2.5 Capacitor Start Capacitor Run Motor
In this motor capacitors are introduced with secondary winding. One capacitor is for a start which is known as optimum start. A second capacitor is during start and run which is also known as running performance.
4 The capacitor is enduringly allied in a series by auxiliary winding as shown in figure 6 and small value is good for this capacitor. The capacitor is parallel connected to the capacitor running and for this capacitor large value is required. After the motor stars the starting capacitor is detached.
Figure 6 - Capacitor start capacitor run motor [1]
1.2.6 Shaded Pole Induction Motor
In this type of induction motors, the stator have significant poles in which one element of each pole have been enclosed by a short circuit shading coil as shown in figure 7. The rotating field moves in the path from un-shaded pole to shaded pole as the flux under un- shaded pole leads the shade pole which is caused due to induced currents. The rotor rotates in the direction from un-shaded pole to shaded pole which is due to low torque that is produced in the motor.
Figure 7 - Shaded pole induction motor [1]
5 1.2.7 Universal Motor
Single phase induction motors like split phase are not self, starting motors. This can be overcome by designing a D.C. motor which can run on a.c. as well. The polarities of armature and field circuits are the basis for the rotation of a D.C machine. The field & armature current reverses concurrently as the direction of the line current reverses and the core loss through alternative flux is low, so that a triumphant single phase induction motor is developed. All this is achieved by using a laminated core and by connecting the armature winding and field winding in series as shown below in figure 8.
Figure 8 - Universal Motor [1]
1.2.8 Synchros -
Synchros are an unusual wound rotor which is used in pairs to endow with the control of the shaft. The rotor has a single phase winding whereas stator has three phase winding as shown in figure 9. Synchros have low friction bearings and inertia to diminish errors and mechanical dampers.
Figure 9 - Low Torque Synchros [1]
6 1.2.9 DC Tachometer In control systems, it is requisite to feedback the voltage comparative to the shaft speed. The feedback of voltage can be attained using direct current tachometers which are a direct current generator in a D.C. servo motor. By using inverter circuit, D.C. tachometer is able to be used on an A.C. servo motor.
1.2.10 AC Tachometer A.C. tachometer is in essence a two phase induction motor. It is useful in feedback systems. In this tachometer, stator windings are used as control and reference windings which are shown in figure 10. An AC Tachometer operation is explained by double revolving field theory. This meter must have low inertia in case of rapid speed variations [1].
Figure 10 - AC Tachometer [1]
7 1.2.11 Two Phase Servo meter To coerce the load and also as sensors to determine position and speed in the feedback system two phase servo meters are used. The rotor has elevated resistance as a rotor is a squirrel cage rotor as in two phase induction motor as shown below in figure 11.
Figure 11 - Two Phase Servo Meter [1]
1.3 Three Phase Induction Motor This induction motor is proficient of working 3-phase supply of alternating voltage. A Squirrel cage induction motor is the best part general kind. These types of induction motors have stator which is an archetypal three phase stator with the twisting relocated by 120 o electrically. In this motor, rotor current is produced by a sinusoidally isolated air opening flux. The linkage between the air opening flux and stimulated rotor currents causes a torque on the rotor.
1.3.1 Working Principle Three phase induction motors are self starting motors. The induction motors in three phase are enclosed by overlapping winding apart by 120 o electrically. The stator winding in three phase a.c. supply creates a rotating attractive field so that it rotates at a
8 synchronous speed. The current is generated by the rotor flux and static rotor relative velocity. According to Lenz's law to lessen the relative velocity produced in the motor, the rotor rotates in the same direction as shown in figure 12. The speed of the rotor should not be equal to the speed of the stator that is synchronous speed as if they are equal the current will not flow which results in no torque generation. The speed difference among stator and rotor is known as slip.
Figure 12 - Working Of Induction Motor In Three Phase [3]
1.3.2 Squirrel Cage Motor Today's induction motors are almost squirrel cage induction motors. The rotor is cylindrical laminated core in this motor and has a simple and imperishable construction. The rotor has parallel slots and these have some recompense as in figure 13. The rotor bars are electrically welded for short circuiting the ends. The bars are enduringly short circuited so that further resistance can be added to the armature circuit.
9
Figure 13 - Squirrel Cage Induction Motor [4]
1.3.3 Phase Wound Rotor The rotor in a phase wound rotor is at all times is wo und in the three phase although the stator is winding in 2 phase. The poles of stator and ro tor in this motor are considered to be in equal quantity . The rotor is internally coupled as a star and the further three ends come outside the motor as shown in figure 14 . Rheostat is implemented in this motor to reduce external resistance.
Figure 14 - Phase Wound Rotor [5]
10 In this paper the induction motor that is implemented is squirrel cage which is built in stationary location. Squirrel cage induction motor is the most utilized three phase induction motor in many electrical industries.
11 CHAPTER 2 - DESIGN THEORY
2.1 Design The fault diagnosis is a very significant role in manufacturing industries as impromptu contraption downtime is able to cause heavy pecuniary losses. The foremost induction motor faults are [6]: • Stator faults • Bearing faults • Eccentricity • Rotor faults To evade the unprepared down time and to lessen other losses, it is essential to develop a fault diagnosing practice to categorize the fault at the untimely phase. The induction motors are premeditated in a stationary frame because it is a suitable reference frame while the supply system is complex. From the comparable circuit replica of the induction motor in a stationary reference, the equations are derivative and executed in Lab VIEW with special stages. The stator fault can be secret into: • Inter turn fault • Single phasing fault and • Insulation failure. In this paper single phase stator fault of the induction motor is calculated. The faults in the rotor can be secret into: • Broken bar rotor and • Rotor eccentricity.
The consequence of the induction motor when both faults are built-in also evaluated for generating the outcome for identifying the fault in the induction motor model. The fault diagnosis procedure observed in this paper is Park's vector model for recognition of the stator and rotor faults using the software Lab VIEW. The induction motors are replicated in a stationary reference by using Lab VIEW. In the induction motor premeditated and customized for producing stator faults are initiated. The results are scrutinized and evaluated by Park's vector method to diagnosis these faults.
12
By using Lab VIEW the motor representation is intended in a stationary reference and the related circuit of an induction machine is shown in figure 15. From this corresponding circuit model of the induction motor, the equations of stationary reference frame are derived [6].
Figure 15 - Induction Motor Circuit Model [6]
The equations, resultant from the corresponding motor model, the induction motor in Lab VIEW with the subsequent six steps.
13 2.1.1 AC Waveform Generation AC waveform is the first pace of the model, in which the in induction motor supply voltage is generated using subsequent sine formulae [6]:
Vas = V m *sinwt (1)
Vbs = V m *sin (wt - 1 20) (2)
Vcs = V m *sin (wt - 240) (3) The supply voltages have to be zero for balanced procedure. The zero sequence current component can be calculated using the following formulae and must be zero in all conditions.
ios =( i as +i bs +i cs )/3 (4)
2.1.2 abc to dq Conversion In abc to dq conversion pace, the produced voltage waveform in a 3 phase is changed in
to the d and q axis components; Vds & V as using the Park's approach [6].
Vqs = (2/3)* Vas – (1/3)* Vbs – (1/3)* Vcs (5)
Vds = (1/ √3)* (V cs - Vbs ) (6)
Vos = (1/3)*(V as + V bs + V cs ) – (1/Csg)*(i as + i bs + i cs ) (7)
where C sg = 1/ 50 * (Z b* Wb).
2.1.3 Q & D Axis Transformation
Q & D axis transformation third pace of the model, using I m, supply phase current maximum value in which the of induction motor are calculated using stator and rotor qdo voltages from the formulae below. The model is developed in the stationary frame as it is an opportune frame of reference [7].
6 Iqs = ∗Im ∗ sinwt (8) 2 6 Ids = ∗Im ∗ sin (wt - π/2) (9) 2
14
2.1.4 Rotor For the rotor the moment of inertia, base speed, a number of poles, rated base power, rotor inductance & magnetizing inductance are used and by using these terms, the torque and speed are calculated [8].
Electromagnetic Torque: Tem = (2* L r/3*p*L m) (10) 2 Motion of Rotor: H = (J*w b )/2*p*s b (11)
2.1.5 Inverse Transformation In Inverse Transformation, the induction motor q and d axis currents are converted in to stationary currents.
ias = i qs + i os (12)
ibs = - (1/2)* iqs – (√3/2)* ids + i os (13)
ics = - (1/2)* iqs + (√3/2)* ids + i os (14)
All these paces are created as five blocks in the Lab VIEW. By combining all these blocks we get the induction motor block in the Lab VIEW. Now for this integrated block, the Park's vector method is applied to diagnosis the fault in the induction motor.
For Phase imbalance faults: voltage was dropped by 20 volts in one of the three phase supplies. To reproduce imbalanced supply faults small correction has to be made to the original model. The equations for stator voltage supply changed as:
Vas =√ (V m −Vo)* cos ωt (15)
Where, Vm is the rated voltage, Vo = 20 V.
15 2.2 Park's Vector Method Park's Vector method is one of the most used approaches in today's electrical industries to diagnosis faults in the motor. The stator line currents are altered in to Park's vector by the equation shown below [9].
2 −1 −1 ia ib ic ids 3 = 6 6 (16) iqs 1 −1 0 ib ic 2 2
By implementing this equation theoretically, if the machine is healthy, we get a perfect circle. If the motor was unbalance due to supply voltage or faults we get an elliptical representation.
16 CHAPTER 3 - SIMULATIONS AND RESULTS
3.1 Introduction To Lab View Park's vector and Lab view has been used in this project for the simulation of the induction motor fault analysis.
In engineering test, virtual technology has made substantial improvement and is widely used in this environment. There are multiple advantages like outstanding ability over common technologies, high performance with virtual technology of instrumentation.
The abbreviation of Lab view: Laboratory Virtual Instrument Engineering Workbench. It's nothing but the software for virtual instruments. This Lab View software combines multiple tools which are come up with software. We can use these built in tools for measurement, testing and control the systems [10]. Lab View can be used in other areas such as monitoring temperature, control systems and simulation.
This Lab View software is a creative advancement, the platform for creating advanced signals or valid world information.
We can use Lab View tool/software in the projects with higher quality within specific time and less human involvement.
3.2 AC waveform generation
The Supply voltages are analyzed in fault and without fault condition by using maximum voltage, frequency and time in AC Waveform generation. In this the supply voltages changes for every change in Maximum voltages as it is dependent on Maximum voltage.
In this paper we are only changing V as in fault condition, so when fault is introduced only
voltage: V as changes and other supply voltages remain the same as shown in the table 1.
17 Vm = 415V Vm = 220V Vm = 110V
Supply Vas Vbs Vcs Vas Vbs Vcs Vas Vbs Vcs voltages
Fault 13406.7 -8625.61 8625.61 6788.23 -4572.61 457.61 3054.7 -2286.31 2286.31
No-Fault 7.149 -8625.14 8625.14 2.06 -4572.61 457.61 9.15 -2286.31 2286.31
Table 1 - AC Wave Form Generation
Figure 16 - Block Diagram In Fault Condition
18 Figure 16 and 17 both are waveform generation block diagrams in Lab View with fault and no fault condition respectively. The fault is introduced by changing one of the source voltage.
Figure 17 - Block Diagram In Healthy Condition
The front panel shown in figure 18 shows both the input and output of the block that we built in Lab View. The relation between input and output are also shown in the front panel for our convince. In this front panel we can see waveform generation inputs and outputs.
19
Figure 18 - AC Waveform Front Panel
3.3 abc to dq Conversion
In this we are converting voltages in abc to voltages in to dq. In this Vqs , Vds and V os are calculated [6]. The voltages in dq are dependent on supply voltages. The voltages Vqs,
Vds , V os will be changing as we change maximum voltage as the supply voltage changes consequently. The voltages: V qs , V os changes when the fault is introduced, but V ds remains the same as this depends on V bs and V cs as shown in figure 19.
Figure 19 - Block Diagram Of abc to dq Conversion
20 The front panel in figure 20 shows both the input and output of the block that we built in Lab View. The relation between input and output are also shown in the front panel for our convince. In this front panel we can see abc to dq conversion inputs and outputs.
Figure 20 - Front Panel for abc to dq Conversion
The abc to dq conversion voltages at different maximum voltage are shown in the table 2 below, where we can observe all voltages in dq are changing with respect to the change
in V m.
Vm = 415V Vm = 220V Vm = 110V
Vqs Vds Vos Vqs Vds Vos Vqs Vds Vos Voltage
1018.23 Fault 8937.83 9960.9 4468.91 4525.48 5280.15 2262.74 2036.47 2640.08
No-Fault 7.14 99960.29 8.50 2.05 5280.15 8.43 9.14 2640.08 8.42
Table 2 - abc to dq Conversion
21 3.4 Q & D Transformation
In Q & D transformation we calculate the currents Iqs , Ids by using current: I m. In this the currents does not change with the change in maximum voltage. This is because they
depend only on current: I m as shown in table 3.
Vm = 415V Vm = 220V Vm = 110V
Currents Iqs Ids Iqs Ids Iqs Ids
Fault -4.91 -18.08 -4.91 -18.08 -4.91 -18.08
No Fault -4.91 -18.08 -4.91 -18.08 -4.91 -18.08
Table 3 - Q & D Axis Transformation
The front panel in figure 21 shows both the input and output of the block that we built in Lab View. The relation between input and output are also shown in the front panel for our convince. In this front panel we can see Q & D Axis Transformation inputs and outputs.
Figure 21 - Front Panel for Q & D Transformation
22
Figure 22 - Block Diagram Of Q & D Transformation
3.5 Torque And Speed
In this block in figure 23 we calculate torque and speed of the motor using the terms: rotor inductance, magnetic inductance, and no: of poles, moment of inertia, base speed and base power. Both speed and torque does not change with change in maximum voltage. They remain same in all conditions and at all voltages.
Figure 23 - Block Diagram Of Torque And Speed
23 The torque and speed outputs are shown in the table 4, both in fault and no fault condition. They are constant for any voltage.
Vm = 415V Vm = 220V Vm = 110V
Torque/ Tem Speed Tem H Tem H H
Fault 0.17 0.08 0.17 0.08 0.17 0.08
No Fault 0.17 0.08 0.17 0.08 0.17 0.08
Table 4 - Torque And Speed Calculation
The front panel in figure 24 shows both the input and output of the block that we built in Lab View. The relation between input and output are also shown in the front panel for our convince. In this front panel we can see torque and speed inputs and outputs.
Figure 24 - Front Panel for Torque And Speed
24 3.6 Inverse Transform
In this block shown in figure 25 we calculate the supply currents: I as , I bs , I os . We calculate these currents by using currents in dq. So, even supply currents remain the same at all voltages and in all conditions.
Figure 25 - Block Diagram of Inverse Transform
The supply currents outputs are shown in the table 5, both in fault and no fault condition. They are constant for any voltage.
Vm = 415V Vm = 220V Vm = 110V
Supply Ias Ibs Ics Ias Ibs Ics Ias Ibs Ics Currents
Fault -4.91 33.77 -28.86 -4.91 33.77 -28.86 -4.91 33.77 -28.86
No Fault -4.91 33.77 -28.86 -4.91 33.77 -28.86 -4.91 33.77 -28.86
Table 5 - Inverse Transformation
25 The front panel in figure 26 shows both the input and output of the block that we built in Lab View. The relation between input and output are also shown in the front panel for our convince. In this front panel we can see inverse transformation inputs and outputs.
Figure 26 - Front Panel for Inverse Transform
3.7 Integrated Block
In integrated block shown in figure 27 all the above five blocks combined to get an induction motor model and Park's Vector is also attached to this integrated block to diagnose the faults in the motor. Voltage is dropped by 20V in the supply in one of the phase for Phase imbalance faults. In order to simulate supply faults in imbalanced circumstance, few adjustment need to be done to the original block.
26
Figure 27 - Block Diagram of Integrated Block
27 The front panel in figure 28 shows both the input and output of the block that we built in Lab View. The relation between input and output are also shown in the front panel for our convince. In this front panel we can see integrated block inputs and outputs and also analysis of the condition by the graph which is the result of the motor.
Figure 28 - Front Panel for Integrated Block
3.8 Results
These are graphs obtained from the integrated block with a fault and no fault condition. Here 3 maximum voltage values are considered and compared the difference between these graphs. Maximum voltages are : 110V, 220V, 415V as these are the most used range of voltages in industries shown in figures: 29, 30, 31, 32, 33, 34. In no fault condition as the voltage increases, the graph is becoming more circular. This shows that at higher voltages we are getting a complete circle which is the best result for a healthy condition.
28 In a fault condition as the voltage increases, the graph is becoming more elliptical. This shows that at higher voltages we are getting a more raidus elliptical which represents fault on the motor. So the best voltage is to be considered is in mid ranges so that the motor in fault and no fault conditions will be in a good range.
Figure 29 - Fault Condition At 110V
Figure 30 - No Fault Condition At 110V
29
Figure 31 - Fault Condition At 220V
Figure 32 - No Fault Condition At 220V
30
Figure 33 - Fault Condition At 415V
Figure 34 - No Fault Condition At 415V
31 The default values that are used in this paper for calculations are just taken from a reference paper but not compared as follows [11]: W: frequency = 50Hz
Zb = 377
Im = 15.3
Wb : Base speed at nominal ratings= 377
Ias , I bs & I cs : Stator currents = 0
ψmd & ψmq : Stator mutual flux linkages in stationary d & q axes P: number of poles in the motor = 4 J: Moment of inertia = 0.090
Sb : Rated base Power = 18000.00
Rs : Resistance in Stator = 0.8160
Rs : Resistance in Rotor= 0.43
XIs : Leakage reactance in Stator = 0.75
Xlr : Leakage reactance in Rotor= 0.754
Xm = 26.130 Lr : Rotor Inductance = 63.30 mH Lm : Magnetizing Inductance = 81.70 mH
32 CHAPTER 4 - FUTURE SCOPE
The system we developed can be still more upgraded by implementing wavelet analysis method. By using the wavelet analysis method, the frequency imbalance can be cleared and the results would be more accurate. In most of the cases, electrical machines diagnosis, the frequency signal has distinguished information which is unknown. The frequency components have frequency spectrum of the signal. The frequencies of signal in the motors are shown in the frequency spectrum. For this many transformations can be used. Fourier Transformation can be applied for this wavelet analysis method. So, by using this method we can know the frequency imbalance.
So, in my next work I would like to work on the wavelet analysis method and implement on this model that I developed in the Lab View and develop a system with no frequency imbalance and a more accurate system.
33 CHAPTER 5 - CONCLUSION
Our aim in this paper is to model an induction motor by building five blocks and then implement Park's Vector to diagnose the faults in the motor using the software Lab View. The simulation output illustrate that our goal is achieved by adequate consequences.
The first step is to design the induction motor in Lab View by means of the equations that are resultant from an equivalent model of the motor one by one and then integrate all these blocks to get an induction motor in Lab View.
The second step is to introduce Park's Vector to the induction motor and do the fault diagnosis. There are two conditions: One is no fault condition and other one is fault condition which is introduced by imbalance stator voltages.
34 REFERENCES
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[11] Lakhya Jyoti Phukon, and Neelanjana Baruah, A Generalized Matlab Simulink Model of a Three Phase Induction Motor, International Journal of Innovative Research in Science, Engineering and Technology (An ISO 3297: 2007 Certified Organization), Vol. 4, Issue 5, May 2015.
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