An Experimental Investigation on Broken Rotor Bar in Three Phase ... · proposes extension of vibrations analysis to detect rotor bar damage in three phase induction motor operating

International Journal of Emerging Technology and Advanced Engineering

Website: www.ijetae.com (ISSN 2250-2459, ISO 9001:2008 Certified Journal, Volume 3, Issue 4, April 2013)

357

An Experimental Investigation on Broken Rotor Bar in Three

Phase Induction Motor by Vibration Signature Analysis using

MEMS Accelerometer Maruthi.G.S.

1, Vishwanath Hegde

2

1Department of Electrical & Electronics Engineering,

Smt.L.V.Government Polytechnic, Hassan-573201, Karnataka State, India e-mail: [email protected]

2Department of Electrical & Electronics Engineering,

Malnad College of Engineering Hassan-573201, Karnataka State, India e-mail: [email protected]

Abstract— Three phase Squirrel Cage Induction Motors

(SCIM) are continuously subjected to electrical, thermal,

mechanical and environmental stresses in any industrial

application. Such stresses can result in rotor bar damage. Due

to such faults an unsymmetrical magnetic field will be setup

and can lead to reduction in developed torque, increase in

speed fluctuations, noise and vibrations. The present work

utilizes the motor vibrations as a medium to detect and

diagnose the broken rotor bars under no load and on load

condition by using state-of-the-art, MMA6270QT MEMS

accelerometer. Spectral analysis of motor vibration signals by

using FFT analysis yields twice slip frequency components

(1±2ks).fs around fundamental frequency and 2sfs frequency

component in low frequency range which indicates rotor bar

damage fault. A simple method has been proposed to compute

severity of fault by comparing the magnitude average of side

band harmonic frequency with fundamental frequency

component. Experimental results have demonstrated the

effectiveness of the proposed technique.

Keywords – Rotor bar damage; MEMS accelerometer; Condition

monitoring; Vibration analysis; Squirrel cage induction motor.

I. INTRODUCTION

Three phase induction motors employed in mining, iron

and steel, petrochemical, wood chipping plant in paper and

pulp industries, stone crushing plant and coal handling in

thermal plant etc., are subjected to more electrical,

mechanical, thermal and environmental stresses. This may

be due to numerous starts and stops, or operating motor

under various load conditions, which leads to abnormal

current flow in rotor circuit [1]. This will lead to

development of porosity in rotor than in a motor that starts

and runs under steady state. Porosity is one of the defects

that is invisible to the naked eye. It will form the initial stage

of broken bar and commonly found in cast aluminum rotors.

A certain level of porosity can be tolerated, but if the

porosity accumulates in one place then it may lead to

formation of crack and hence bar damage.

This will set up asymmetrical rotor magnetic field and

causing pulsation in speed and torque. As a result high

vibrations, noise and excessive heating sets up in the motor.

This may also results into bearing damage, rotor-stator rub,

thus causing potential damage to rotor core as well as stator

insulation [2-3]. Since the rotor bar damage is an unseen

fault and causes no immediate damage to motor, the

identification, diagnosis and isolation of faults become

challenging task for maintenance engineers. To achieve this,

industry demands simple, cost effective, reliable, portable,

low power consumption, compact size, condition monitoring

device [1].

The motor failure survey related to rotor faults conducted

by IEEE -Industrial Application Society (IAS) reports 8%,

Electrical Power Research Institute (EPRI) reports 9%.

Both survey focused on medium size machines. Allianz

focused on medium to high-voltage large induction

machines, reports 13% failure [4]. The rotor related failures

are more in medium to high voltage motors than small

machines. This is due to the fact that, these categories of

motors are usually employed in high starting torque and

critical applications, where thermal stresses are high due to

abnormal starting current and chances of rotor failure is

more. Hence condition monitoring of them helps to avoid

premature failure. The conventional methods employed by

past researchers in rotor bar damage detection are,

temperature measurement, infrared recognition, axial flux

measurement, measurement of speed, radio frequency (RF)

emission monitoring, and accoustic measurement.The fault

detection based on these methods are invasive, time

consuming, costly and less reliable [4-5].

Based on the stator current as medium, the researchers

[1], [3], [6], [7] and [8] have employed classical side band

harmonic frequency approach to detect the broken rotor

bars. In [7], four, five and six rotor bar damage has been

detected under no load, 65% and 100% load condition.



358

Authors have shown rated speed as 1410 rpm from the

name plate details of motor but during the course of

conducting experiment on faulty motor under 65% and

100% load, 1455 rpm and 1425 rpm respectively have been

recorded, which is practically not possible. Also, practically

a motor with three, four, five and six broken bar will not be

able to drive the load because of decrease in average torque

and reduction in speed. In this regard the paper [7] has to be

critically viewed. In [8], authors have detected mixed fault

diagnosis (rotor bar damage and eccentricity fault) with one

broken bar with eccentricity, two broken bar with

eccentricity and three broken bar with eccentricity. It has

been reported in the paper that speed is kept at 1440 rpm in

all cases. But practically it is impossible with broken rotor

bar motor. This is because of reduction in magnetic flux due

to broken bars, as result there will be reduction in speed.

Also, the authors do not clearly indicate the loading details

and speed of the motor under different fault cases.

The other approaches employed by researchers are,

entropy probability distribution of featured current signal

using Hilbert transform discussed in [9]. Measurement of

zero crossing time (ZCT) instants of stator current was

another approach employed in [10]. Authors have noticed

2sfs frequency components in ZCT signal with rotor fault

and indicated it as fault detector. This method demands

additional hardware circuitry to extract ZCT signals and

digital filtering techniques are needed to make system on

line. Hence the complexity and cost increases. Advanced

signal processing technique like wavelet transform and

Finite element method (FEM) have been employed in [11]

and [12]. The fault analysis based on these methods requires

good knowledge on wavelets and FEM to identify the fault

and its severity, which will be complex from the industrial

point of view. Also, FEM takes more computational time

and computer memory to analyze the motor fault detection.

Hence on line fault detection is difficult. In [13], authors

have proposed a new control strategy to control the speed

and torque in inverter driven induction motor. The

computation of variance under normal and faulty condition

shows that variance value is more under faulty condition

than normal. This method is based on dynamic response of

control strategy and is less sensitive for smaller rotor faults.

A clear distinction between fault cases with less number of

broken bars (e.g., zero versus one broken bar) is therefore

not possible in the above method.

Vibration analysis is another approach employed in [14-

17] to detect rotor bar damage in induction motors. The

classical side band harmonic frequency analysis has been

carried out on vibration signals. In [14-17] authors have

employed conventional piezo electric accelerometers for

vibration analysis. But these accelerometers are having

limitation of measuring only short duration vibration

measurement. This is due to the fact that sustained

piezoelectric action will cause overheating of crystals and

thus deteriorate their conversion capability [18]. Hence

vibration monitoring using these accelerometers will not be

accurate. In [19], authors have studied the vibrations

developed in induction motors due to rotor imbalance by

changing the external weights to motor shaft using MEMS

accelerometer. Authors have implemented the ZigBee IEEE

802.15.4 protocol for remote sensing of data for condition

monitoring. No studies regarding broken rotor bar detection

have been reported. The severity of broken rotor bar fault

under different load conditions has not been addressed in the

above referred literature.

Recent developments in semiconductor technology have

contributed the state-of-the-art MEMS accelerometers [20].

The MMA6270QT is one among them employed in the

present work. The promising features have drawn the

attention of researchers to employ them in detection and

diagnose faults in motors cost effectively.

The published literature unfolds the fact that MCSA gives

efficient results when motor operates under loaded

condition. But, when motor operates under no load running

condition, the side band frequency component (1 ± 2ks).fs

are very close to the supply frequency component fs, a

natural spectral leakage can hide characteristics frequency

components of the fault. In this case standard MCSA

method fails to detect broken bar faults. Hence, fault

detection based on MCSA is dependent enough on load and

broken bars. The limitations of MCSA and conventional

accelerometers have drawn the attention of researchers for

alternative method. In this direction the present work

proposes extension of vibrations analysis to detect rotor bar

damage in three phase induction motor operating under

variable load conditions using MEMS accelerometer. A

simple and easy method has been proposed to find severity

of fault, which will be based on comparing the magnitude of

side band harmonic frequency with fundamental frequency

component.

II ROTOR BAR DAMAGE ANALYSIS

The classical twice slip side band harmonic frequency

approach employed to detect the broken bar fault [3], [4-13]

is given by 1 2br sf ks f (1)

where fbr = broken bar frequency in Hz; k = 1, 2, 3...

any integer, s = slip and fs = supply frequency in Hz. The

lower side band(1-2s)fs is fault related, while the upper side

band (1+2s)fs is due to consequent speed oscillations.

In the present work, a simple method to find out

percentage fault severity factor has been proposed in

equation (2). It can be used as diagnostic index for

preventive maintenance.



359

Magnitude_Average_of (1 2. ).%SF 100

Magnitude_of ( )s

ss fX

f

(2)

where %SF = percentage severity factor; (1-2s).fs =

magnitude of left hand side, and (1+2s).fs = magnitude of

right hand side harmonic frequency component.

III. EXPERIMENTAL SETUP OF PRESENT WORK

An experimental set up of present work is shown in Fig.1

for investigating rotor bar damage in induction motor under

no load, half load and full load conditions. The test setup

consists of motor with rating 3 phase, 1.5 HP, 415 V, 50 Hz,

1440 rpm, 28 bar rotor, 36 stator slots with mechanical load.

A healthy rotor, one broken bar and two broken bar rotors

are used with common healthy stator, which is as shown in

Fig.2 (a) and (b).

Fig.1 Experimental setup of the present work

Fig.2 (a) Healthy motor rotor (b) Rotors with one and two broken bar

The instrumentation includes MEMS accelerometer, a high

resolution FFT analyzer and a personal computer connected

to FFT analyzer through RS-232 cable. In the initial stage of

present work, Tektronics100 MHz storage oscilloscope,

which has inbuilt FFT analysis provision is made use for

carrying out FFT operation on accelerometer output signal.

The sampling rate of 2.5 kilo samples/second over span of 1

kHz, 0.5 kHz and 0.25 kHz for 10 seconds have been used to

study high frequency and low frequency range fault signals

by using rectangular window.

II. RESULTS AND ANALYSIS

Case 1: Healthy motor running under no load condition VRY = VYB = VRB = 415 Volts,

IR = IY = IB = 1.1 Amps; N = 1440 rpm; s = 0.04

(a)

(b)

(c)

(d) Fig.3 FFT spectrum of healthy motor (a) 1.5 HP, No load condition and

5 HP (b) No load (c) Half load (d) Full load condition

Observations:

When a balanced three phase supply voltage is applied to

healthy induction motor, uniform current flows in all the

phases. This will set up a uniform magnetic field both in

stator and rotor. The interaction of mmf in rotor circuit with

stator magnetic flux will produce steady positive motor

torque, which drives the rotor in forward direction producing

useful mechanical output. A fine radial vibration will be

setup in the stator. The spectral analysis of vibration signal

yields dominant 49.81 Hz frequency component with

magnitude of 68.21 dB and no side band harmonic



360

frequencies as seen from Fig.3 (a). Also, similar kind of

experiments are conducted on healthy motor with 5 HP, 415

V, three phase squirrel cage induction motor under no load,

50% load and 100% load and the corresponding FFT

spectrum are shown in Fig.3 (b),(c) and (d). The percentage

severity factor computed using equation (2) for 5 HP motor

are 15.18 %, 16.59 % and 19.09 %. The 49.81 Hz which is

very close to 50 Hz frequency component is a positive

sequence component which is essential for driving rotor in

forward direction and this component is an indicator of

healthy motor.

Case 2: Test motor (one and two broken rotor bars) running

under no load condition. IR = 1.7 Amps, IY = 1.8 Amps, IB = 1.8 Amps

VRY= 410 Volts, VYB = 410 Volts, VRB = 410 Volts

(a)

(b) Fig.4 FFT spectrum of (a) one broken bar (b) two broken bar – No

load condition Table -1 Experimental and analytical values of side band harmonic

frequency components -No load condition

Side band

frequencies

Experimental Values Analytical values

of Frequency

(Hz) One Broken Bar Two Broken Bar

Freq. in

(Hz)

Amplit

ude in

(dB)

Freq.

in (Hz)

Amplitu

de in

(dB)

One

broken

bar

Two

broken

bar

(1-4s)fs 37.48 28.81 35.26 31.61 38.0 36.0

(1-2s) fs 43.65 38.81 42.66 37.61 44.0 43.0

fs 49.91 64.01 49.81 61.21 50.0 50.0

(1+2s) fs 56.23 33.21 56.97 36.41 56.0 57.0

(1+4s) fs 62.39 32.81 64.12 35.61 62.0 64.0

2ksfs 6.165 20.41 7.152 25.61 6.0 7.0

Case-3: Test motor (one and two broken rotor bars) running

under half load condition. IR = 2.5 Amps, IY = 2.8 Amps, IB = 2.8 Amps

VRY= 400 Volts, VYB = 399 Volts, VRB = 400 Volts

(a)

(b)

Fig. 5 FFT spectrum of (a) one broken bar (b) two broken bar – half load

condition

Table -2 Experimental and analytical values of side band harmonic

frequency components –Half load condition

Side band

frequencies

Experimental Values Analytical

values of

Frequency (Hz) One Broken Bar Two Broken Bar

Freq.

in (Hz)

Amplit

ude in

(dB)

Freq. in

(Hz)

Amplit

ude in

(dB)

One

broken

bar

Two

broken

bar

(1-4s)fs 25.15 26.01 33.79 28.01 25.4 34.16

(1-2s) fs 37.48 33.61 41.92 37.61 37.7 42.08

fs 49.81 63.61 49.81 60.41 50 50

(1+2s) fs 62.14 39.21 57.71 35.21 62.3 57.92

(1+4s) fs 74.48 26.81 65.6 38.41 74.6 65.84

2ksfs 12.82 21.61 7.89 25.61 12.3 7.92

Case 4: Test motor (one and two broken rotor bars)

running under full load condition. IR = 3.4 Amps, IY = 3.6 Amps, IB = 3.6 Amps

VRY= 391 Volts, VYB = 392 Volts, VRB = 392Volts

(a)



361

(b)

Fig. 6 FFT spectrum of (a) one broken bar (b) two broken bar – full load condition

Table -3 Experimental and analytical values of side band harmonic

frequency components –full load condition

Side band

frequencies

Experimental Values Analytical values

of Frequency

(Hz) One Broken Bar Two Broken Bar

Freq. in

(Hz)

Amplit

ude in

(dB)

Freq. in

(Hz)

Amplit

ude in

(dB)

One

broken

bar

Two

broken

bar

(1-4s)fs 18.74 22.81 31.32 29.21 18.33 31.6

(1-2s) fs 34.03 32.41 40.44 42.41 34.07 40.8

fs 49.81 59.21 49.57 57.61 50 50

(1+2s) fs 65.1 36.41 58.69 32.42 65.54 59.2

(1+4s) fs 80.89 26.81 67.82 36.41 81.28 68.4

2ksfs 11.84 16.41 9.124 22.81 15.73 6.6

Observations:

Referring to case-2, due to broken bar rotor, an unequal

amount of current flows in rotor will set up an asymmetrical

magnetic field. The interaction between asymmetrical rotor

mmf and stator field produces a pulsating torque. This will

sets up vibrations in the motor. Speed has reduced and slip

increased; Nr = 1407 rpm; Slip = 0.0618 (one broken rotor)

and Nr = 1392 rpm; Slip = 0.0717 (two broken rotor) even

running under no load condition. The spectral analysis of

motor vibration shows frequency component of 49.81Hz

with amplitude 64.01dB amplitude for one broken rotor bar

and 49.81Hz with amplitude 61.21dB amplitude for two

broken rotor bar as shown in Fig.4 (a) and 4(b). The left

hand side (1-2ks) fs and right hand side (1+2ks) fs band

frequency components exists due to rotor asymmetry and

speed fluctuation. Table-1 presents the fault frequency and

its amplitude for one and two broken rotor bar under no load

condition.

Referring to case-3, as the load on test motor increased

to 50 % of its rated value, current increases, speed decreases

and slip increases, Nr = 1314 rpm; Slip = 0.123 (one broken

rotor) Nr = 1381 rpm; Slip = 0.0792 (two broken rotor). The

effect of asymmetrical magnetic field will be more as

compared to no load condition. As a result pulsating torque

and speed oscillations setup in rotor will develop vibrations

and humming noise in motor. The spectral analysis of

vibration signals shows that the magnitude of side band

frequencies fb = (1 ± 2ks) fs increases as compared to case-2,

which is shown in Fig.5 (a) and (b). Table-2 presents the

magnitude and frequency of side band harmonic frequency

components for one and two broken bar under half load

condition.

Referring to case-4, as the load on the faulty motor

increased to its full load value, the terminal voltage and

speed decreases with increase of slip Nr = 1263 rpm; Slip =

0.158 (one broken rotor), Nr = 1398 rpm; Slip = 0.0920 (two

broken rotor). The magnetic asymmetry in the rotor and

speed oscillation increases, as a result more vibration will

set up in the motor. The magnitudes of side band harmonic

components fb = (1 ± 2ks).fs are increases as compared to no

load and half load condition which is as shown in Fig. 6(a)

and 6(b). Table-3 presents the magnitude and frequency of

(1± 2ks) fs sideband harmonic components under full load

condition. In all the cases, the experimental results are

validated analytically using equation (1) and found results

are closely matching.

Fig. 7 Comparison of FFT spectrum one and two broken bar – No load

condition

Fig. 8 Comparison of FFT spectrum one and two broken bar – Full load

Fig.7 and Fig.8 shows the comparison of one broken bar and

two broken bar rotor operating under no load and full load

condition. The magnitude of side band harmonic frequency

component in two broken bar is more than the one broken

bar in both cases. Also, as load increases not only magnitude

increases but frequency of side band harmonic component

shifting away with respect to fundamental has been

observed.



362

Table -4 Percentage severity factor for present work motor

% Load Healthy

Motor

% Severity factor (%SF)

One

Broken Bar Two

Broken Bar No Load

(0 %) 15.18 56.25 58.83

Half Load

(50 %) 16.59 57.23 60.27

Full Load

(100 %) 19.09 58.11 64.94

The percentage severity factor (%SF) of broken bar fault has

been computed for present test motor by using equation (2)

is tabulated in Table.4. Fig.9 shows the percentage severity

of fault with no load, half load and full load condition. To

ensure the effectiveness, consistency and repeatability of

proposed method of finding percentage severity factor as in

equation (2), it has been applied to the experimental and

simulation results of different rating of induction motor

under different loading conditions of past researchers and

found the following results as tabulated in Table 5.

Fig.9 Percentage severity factor (%SF)

Table -5 Percentage severity factor for past researchers results

Healthy

Motor

% Severity factor (%SF)

One Broken Bar

Two

Broken

Bar

Three

Broken

Bar

Four Broken

Bar

Five Broken

Bar

Note: A 3 phase 0.5 HP induction motor employed for one

broken bar analysis with 25% load condition [7 ]

34.61

-

48.33

56.45

Expt. result

Simulation result

Note: A 3 phase 2 HP induction motor employed for four &

five broken bar analysis with 65% load condition [8].

34.21 - - - 58.82 61.76

Note: A 3 phase 5.5HP induction motor employed for one, two

and three broken bar analysis with 100% load [10].

27.7 44.44 53.7 57.40 - -

Note: A 3 phase 3HP induction motor coupled with dc

generator employed for one, two and three broken bar

analysis [16]. Side band components not visible for healthy

case.

- 50 54.28 57.14 - -

It is clear from Table.4, Table.5 and Fig.9, that fault severity

increases with i) increase of load and ii) increase of broken

rotor bar. Based on the above following observations have

been made,

If %SF < 45% then rotor is healthy

else if %SF > 45% and < 58% then

one broken rotor bar fault

else if %SF > 58% and < 65% then

two broken rotor bar fault

else if %SF > 65% then

three or more broken rotor bars

IV. CONCLUSION

In the present work, experimental results and analysis of

broken bar detection based on vibrations of the motor

operating under no load, half load and full load condition by

using MMA6270QT MEMS accelerometer have been

presented. The experimental results show that presence of

twice slip frequency (2sfs) due to pulsation in torque in low

frequency range and side band harmonic frequency

components (1±2ks).fs around fundamental frequency

component can be a clear indicator of rotor bar damage

fault. As the numbers of broken bars are more, the side band

harmonics (1±2ks).fs increases followed with more

vibration, humming noise and reduction in motor torque.

Also, as the load varies on broken bar motor, the amplitude

of side band harmonics (1±2ks).fs increases. As a result the

severity of fault increases leading to premature failure.

Presently research work is in progress to detect other

abnormalities in induction motor.

ACKNOWLEDGEMENT

Authors would like to express gratitude to

Sri.Venkataramana Bhat, Managing Director, NIKHARA

Electrical and Allied Technology, an ISO 9001 Company,

Bangalore, for supplying induction motors with rotor bar

damage.

REFERENCES

[1] D K Soni,“Condition monitoring of HT Motors”, 7th

International conference on electrical rotating machines

(ELROMA 2008),Topic IV, pp.1-16, Jan 21-22,2008, Mumbai, India.

[2] Austin H Bonnet and George Soukup, “Analysis of rotor failures in squirrel cage induction motors”, IEEE Transactions on

industry applications, Vol.24, No.6, Nov-Dec 1988

[3] Astrit Bardhi, Ymer Luga and Myrteza Braneshi, ”Determination of defect in rotor of induction machine by

spectral analysis of stator phase current”,Perspectives of

innovations, Economics and Business, Vol.6, pp.1-6; issue 3,

2010.

[4] Pinjia Zhang, Yi Du, Thomas G. Habetler and Bin Lu, “ Survey

of Condition Monitoring and Protection Methods for Medium- Voltage Induction Motors”, IEEE Transactions on Industry

Applications, Vol.47, No.1, January/February 2011.



363

[5] M.H.Benbouzid, “A Review of induction motor signature

analysis as a medium for faults detection”, IEEE Transactions on industrial electronics, Vol.47, No.5, October 2000.

[6] M.Messaoudi, L.Sbita, “Multiple Faults Diagnosis in Induction

Motor using MCSA Method”, International Journal of Signal and Image Processing, Vol.1, Issue.3, pp.190-195, 2010.

[7] Szabo Loránd, Dobai JenőBarna and Biró Károly Ágoston,

“Rotor Faults Detection in Squirrel-Cage Induction Motors by Current Signature Analysis”, IEEE-TTTC International

Conference on Automation, Quality and Testing, Robotics, Cluj-

Napoca, Romania, pp.1-6, May 13 – 15, 2004. 2004,

[8] Zhenxing Liu, Xianggen Yin, Zhe Zhang, Deshu Chen and Wei

Chen , “ On line rotor mixed fault diagnosis way based on

spectrum analysis of instantaneous power in squirrel cage induction motors”, IEEE Transactions on Energy conversion,

Vol-19, pp 485-490, No.3, September 2004.

[9] Ilhan Aydin, Mehmet Karakose and Erhan Akin,”A new method for early fault detection and diagnosis of broken rotor bars”,

Journal on Energy Conversion and Management, Vol.52, pp.1790-1799, 2011

[10] Hakan Calis and Abdulkadir Cakir, “Experimental study for

sensorless broken bar detection in induction motors”, International journal on Energy Conversion and Management,

Vol.49, pp.854-862, 2008.

[11] Khalaf Salloum Gacid and Hew Wooi,”Wavelet fault diagnosis and tolerant of induction motor: A review”, International

Journal on the Physical Sciences Vol.6 (3), pp.358-376,4th

February, 2011. [12] J. Faiz, B. M. Ebrahimi and M. B. B. Sharifian, “Time Stepping

Finite Element Analysis of Broken Bars Fault in a Three-Phase

Squirrel-Cage Induction Motor” Progress In Electromagnetics Research, PIER , Vol.68,pp. 53–70, 2007

[13] Mitja Nemec, Klemen Drobniˇc, David Nedeljkovi´c, Rastko

Fišer and Vanja Ambrožiˇc,” Detection of broken bars in induction motor through the analysis of supply voltage

modulation”, IEEE Transactions on Industrial Electronics, Vol.

57, No. 8, pp.2879-2888 August 2010 [14] W.T.Thomson and Philip Orpin,“ Current and Vibration

monitoring for fault diagnosis and root cause analysis of

induction motor drives”, Proceedings of 31st Turbo Machinery Symposium, pp.61-67, 2002.

[15] Mariana Iorgulescu and Robert Beloiu, “Vibration and Current

Monitoring for Fault’s Diagnosis of Induction Motors”, Annals

of the University of Craiova, Electrical Engineering series, No.

32,pp.102-107; ISSN 1842-4805; 2008

[16] B.Liang, S.D.Iwnicki and A.D. Ball, “Asymmetrical stator and rotor fault detection using vibration, phase current and transient

speed analysis”, Journal on Mechanical systems and signal

processing, Elsevier Science Ltd, Vol.17 (4), pp.857-869, 2003. [17] C Wang and J C S Lai, “Vibration analysis of an induction

motor”, Journal of Sound and vibration, Vol.224 (4), pp.733-

756, 1999. [18] Tai-Ran Hsu, “MEMS and Microsystems Design and

Manufacture” , Eleventh reprint, Tata McGraw Hill Education

Private Limited, 7,West Patel Nagar, New Delhi, 2010. [19] Suratsavadee Korkua, Himanshu Jain, Wei-Jen Lee and Chiman

Kwan,” Wireless health monitoring system for vibration

detection of induction motors”, IEEE Copy right material, pp.1-6, 2010.

[20] Freescale Semiconductors Inc, USA; www.freescale.com

http://www.freescale.com/

Documents

An Experimental Investigation on Broken Rotor Bar in Three Phase ... · proposes extension of vibrations analysis to detect rotor bar damage in three phase induction motor operating