1. NdFeB powder was weighed for 21.2g.
2. 5 wt% of epoxy binder which is 1.06g was weighed.
3. Both powder and binder were mixed in acetone. The mixture was blended by a mixer until the acetone evaporated and left the mixture in a paste form.
4. The paste was then compressed in a die using auto press machine. The compression load used was 5 tonne.
5. The samples prepared were cured in an oven for 1 hour at 150 °C.
6. The dimensions and weight of each sample were measured to calculate the density of the samples.
7. All samples were then analysed by using optical microscope, Scanning
33.5 Proce
1) The n 2) NdF 3) Volta 4) Read 5) The v 6) Step 7) Step
Fi
edure for tes
necessary co eB magnet i age is increa ding of the sp
voltage is in 5 is repeate 1 to 6 is rep
igure 3.1: Fl
sting of the
onnection fo is placed at t ased until the
peed is taken ncreased for
d for the sam peated for fer
ow chart for
DC Motor
or the power the motor bo e motor start n and record 0.5V and tak me voltage in rrite magnet
r fabricating
supply and m ody
t to rotate.
ded using Ta ke the readin ncrement up t
the sample
motor is per
achometer.
ng p to 6 V
rformed
Figure 3.2: Configuration for the DC motor testing Tachometer
DC Motor
DC Power
Magnet
4.1 Analys
Fig
sis of DC Mo
gure 4.1: Gra
CH RESULT
otor Perfor
aph of Speed
HAPTER AND DIS
mance
d vs Input Po
4
SCUSSION
ower for DC
N
C motor (conntrol)
Figure 4.2: Graph of Speed vs Power Input for a DC Motor by using Ferrite Magnet
Figure 4.3: Graph of Speed vs Power Input for a DC Motor by using NdFeB Magnet
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Speed (RPM)
Input Power (Watt)
Speed vs Power Input (Ferrite Magnet)
0 500 1000 1500 2000 2500 3000 3500 4000 4500
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Speed (RPM)
Input Power (Watt) Speed vs Power Input (NdFeB)
Figure 4.4: Graph of Speed vs Power Input for a DC Motor by using Ferrite Magnet, NdFeB Magnet and control plotted in same axis
Figure 4.5: Graph of speed vs power input for a DC motor by using NdFeB Magnet scattered plotted with and without starter assist
0 500 1000 1500 2000 2500 3000 3500 4000 4500 5000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Speed (RPM)
Input Power (Watt)
Speed vs Input Power
NdFeB Magnet Ferrite Magnet control
0 500 1000 1500 2000 2500 3000 3500 4000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Speed (RPM)
Input Power (Watt) Speed vs Input Power (NdFeB)
without starter with starter
Figure 4.6: Graph of speed vs power input for a DC motor by using Ferrite Magnet scattered plotted with and without starter assist
Figure 4.1 , 4.2 and 4.3 show the speed of the DC motor read by using tachometer plotted against power input for the control, ferrite magnet and NdFeB magnet respectively. Power input of the motor was varied by regulating the voltage of the power supply. The linear plot of each graph showing the speed increasing linearly starting from zero for a given power input. For comparison purpose, the linear plot of all 3 situations is put on 1 axis as shows in Figure 4.4. Obviously we can see that using NdFeB magnet increases the speed of the DC motor. The percentage of increment of the speed is 38.3%. Please refer to Appendix C for the calculation.
However, when the graph is plot using scatter plot as show in figure 4.5 and 4.6, we can see that the motor is rotating upon the application of current to the ammature. Certain power input is needed to be applied before it starts to rotate. For instance, as shows in Figure 4.6, for DC motor with bonded NdFeb Magnet, it only start to rotate at 0.0447 watt without starter assisted. This is due to the attraction of the permanent magnet to the stator. It starts to rotate when the magnetic field of the armature is able to overcome the strong magnetic field from the permanent magnet.
0 500 1000 1500 2000 2500 3000 3500 4000
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35 0.4
Speed (RPM)
Input Power (Watt)
Speed vs Input Power (Ferrite Magnet)
without starter with starter
Meanwhile, DC motor with bonded NdFeB Magnet is able to rotate at low power with start assist.
4.2 Metallography Analysis
Figure 4.7: Optical microscope image of the NdFeB Magnet
Figure 4.8: Scanning Electron Micrograph (SEM) image of the NdFeB Magnet
The NdFeB alloy powder with 5wt% epoxy was observed under the optical microscope at 100x magnification and these are depicted in Figure 2.7. The above micrographs show that the particles of the powder are bonded to each other closely by epoxy. So far, the pores could not be seen because of the well distribution of the epoxy binder and hardener. The mixing process with acetone to dilute the resin and hardener also helps to obtain homogeneous mixture. The SEM image is also confirmed that there is no large pores exist.
SEM image also show the grain size of the NdFeB alloy which is around 20 to 50 µm. Besides, the image also shows the random or amorphous grain structure of the alloy. It is due to the rapid quench of the melt NdFeB alloy by the melt spinning process.
Chemical Analysis Using SEM with EDAX
Figure 4.9: Qualitative analysis of NdFeB ribbon (NQP-C)
Element Weight % Atomic % Fe K 70.39 84.81
Zr L 5.09 3.76
Nd L 24.52 11.44 Totals 100.00 100.00
T a r t u m
4
The presenc analysis sho ribbon NQP this analysis usually foun magnets, bu
4.3 Magn
Figu
‐4.00E
ce of elemen ows that not P-C, element s, the result nd in NdFeB ut it is too litt
netic Proper
ure 4.10: Ma F
‐4
‐3
‐2
‐1 0 1 2 3 4
+04 ‐2.00E+
Hyst
nts in the allo t only neod ts such as Z shows that B materials tle and canno
rties Analysi
agnetization, Ferrite and M 4.00E+04 3.00E+04 2.00E+04 1.00E+04 0.00E+00 1.00E+04 2.00E+04 3.00E+04 4.00E+04
+04 0.00E+00 teresis Loop
oy were reve dymium, iron Zirconium w
the fundame are present.
ot be picked
is
B versus Ap Melt Spun N
0 2.00E+04 of Ferrite an
ealed using S n and boron was also app
ental elemen . Boron is p d up by the S
pplied Field, NdFeB Magn 4.00E+04 nd NdFeB M
SEM with E n appear in eared in the nts, neodym present withi SEM analysis
, H hysteresi net
Magnet
Ferrite NdFeB
EDAX. EDA the magnet e materials.
mium and iro in the NdFe s.
is loop for th e Magnet B Magnet
AX tic In on, eB
he
Figure 4.11: Second Quadrant of Ferrite and NdFeB Magnet Hysteresis Loop
Figure 4.12: Energy Product (B vs BH) of Ferrite Magnet and NdFeB Magnet
From the hysteresis loop of the magnet for NdFeB magnet as in Figure 4.10, we can see that bonded NdFeB Magnet comprise a good properties of a good magnet for DC motor application with High value of M and H. While Figure 4.12 shows the BHmax for NdFeB magnet reaches to 8.0 MGOe. As compared to Ferrite Magnet, shows the energy product BHmax of 0.7 MGOe. We can say that bonded NdFeB
‐1.00E+03 0.00E+00 1.00E+03 2.00E+03 3.00E+03 4.00E+03 5.00E+03 6.00E+03
‐8.00E+03‐6.00E+03‐4.00E+03‐2.00E+03 0.00E+00 2.00E+03
Second Quadrant of Ferrite and NdFeB Magnet Hysteresis Loop
Ferrite Magnet NdFeB
‐1.00E+03 0.00E+00 1.00E+03 2.00E+03 3.00E+03 4.00E+03 5.00E+03 6.00E+03 7.00E+03 8.00E+03
‐1.00E+07 ‐5.00E+06 0.00E+00 5.00E+06
BHmax of Ferrite and NdFeB magnet
BH max NdFeB BH max Ferrite Magnet
permanent magnet part of a DC motor can be miniaturized 11.4 times smaller when we replace it with bonded NdFeB magnet.
CHAPTER 5
CONCLUSIONS AND RECOMMENDATIONS
5.1 Conclusion
In the nutshell, the speed of the DC motor was improved when replacing the bonded NdFeB magnet. The speed tested improved by 38.3 % as proven from the calculation and data obtained. It is due to the large value of magnetic field from the ammature and permanent magnet that has been cut through. The high energy of the stator which is from the NdFeB Magnet helps to push the rotor or the amature faster.
However, at very low power input, DC motor with NdFeB Magnet cannot be started.
It is due to the attraction of the magnet to the stator is too strong. The motor only will start to rotate when the magnetic force from the stator is able to push the rotor after the strong magnetic force from the NdFeB magnet. From the above result, it is possible to replace ferrite magnet with NdFeB magnet of the DC motor. Thus, higher performance of the DC motor can be achieved.
5.2 Recommendation
During the testing of the DC motor, it is noted that the reading of the DC motor with ferrite magnet is not consistent. The value measured is slightly increased when it is tested after measuring the speed of the DC motor with NdFeB magnet. It is believe that the strong magnetic field from the NdFeB magnet had retained to the motor’s parts. Thus to overcome this problem, we can test the DC Motor with Ferrite magnet first followed by DC motor with NdfeB magnet.
Besides that, due to the limitation of equipment and instrumentation, the torque of the motor cannot be measured. This study can be value added if we can measure the torque of the motor which by having the value we can calculate the output power of the shaft. By having the value we can calculate the efficiency of the motor and compare the overall performance of the motor.
REFERENCES
[1] M.L Patel, S. Pandian and B.D Pathak, Sintered NdFeB Magnet- Its Potential in Device Application, Indo-ASEAN cost project DMRL Hydrabad. India [2] Mohmad Soid bin Selamat, Application of NdFeB Magnets, AMREC SIRIM
Berhad.
[3] P. Hussain, Shahida Ishak*, M.H. Saleh, M. Mohammad, A. Shaban, S.
Omar and A. Idris Fabrication of pressureless made polymer bonded NdFeB magnet and its magnetic and physical properties in comparison to compacted bonded magnet and ferrite magnet,
[4] William F. Smith, Foundation of Material Science and Engineering, McGrawHill
[5] Serope Kalpakjian, Steven Schmid, Manufacturing Engineering and Technology, fifth edition in SI unit, Prentice Hall
[6] T.R Anantharamam, C. Suryanarayana, Rapidly Solidified Metals, Trans Tech Publications
[7] Zhongwu Liu, Hywel A. Davies, Composition and Microstructure Dependent Spin Reorientation in Nanocrystalline (Nd-Pr)-(Fe-Co)-B Alloys, IEEEE [8] Bonded Nano-composite NdFeB Permanent Magnet, M.H Saleh, M.I
Abdullah, M.S. Selamat, P. Hussain, A.Idris
[9] Melt Spinning Procedure, Mechanical Engineering Department, Universiti Teknologi Petronas
[10] Electric Machinery Fundamentals, Fourth Edition, Stephan J. Chapman, Mc Graw-Hill International Edition.
[11] Basics of Electric Motors Including Polyphase Induction and Syncronous Motor , Anthony J. Pansini, Pennwell Publishing Company
[12] Permanent Magnet Motor Technology (design and applications), second edition, revised and expanded, Jacek F. Gieras, Mitchell Wing, Marcel Dekker Inc.
[13] http://lancet.mit.edu/motors/motors3.html#power , 21 March 2008, 8:30pm [14] http://en.wikipedia.org/wiki/Torque_and_speed_of_a_DC_motor 21 March
2008, 8:30pm
[15] http://en.wikipedia.org/wiki/Brushed_DC_Electric_Motor 21 March 2008, 8:30pm
[16] www.yormag.com/product/compare4.gif , 15 August 2007, 9:30pm [17] http://en.wikipedia.org/wiki/Magnet, 12 August 2007,9:30pm
[18] http://en.wikipedia.org/wiki/Melt_spinning, 20 September 2007,7:30am [19] http://en.wikipedia.org/wiki/Periodic_table , 20 September 2007, 7:30am [20] http://hyperphysics.phy-astr.gsu.edu/hbase/hph.html, 20 September 2007,
7:30am
[21] www.yormag.com/product/compare4.gif , 15 August 2007, 9:30pm
[22] http://www.epoxyandepoxyflooring.com/epoxyresins/epoxyresins.htm, 2 April 2008, 8:00 pm
[23] http://www.geosci.ipfw.edu/XRD/techniqueinformation.html , 5 April 2008.
8:00pm
APPENDICES
APPENDIX A
Tables of Voltage, Current, Power Input, and Speed
Voltage,V Current,I Input power,
watt Speed,
RPM
0.99 0.02 0.0198 0
1 0.02 0.02 407
1.5 0.02 0.03 670
2 0.02 0.04 1034
2.5 0.03 0.075 1306
3 0.03 0.09 1546
3.5 0.03 0.105 1869
4 0.03 0.12 2135
4.5 0.04 0.18 2425
5 0.04 0.2 2653
5.5 0.05 0.275 2935
6 0.05 0.3 3185
Table A1: Control(without starter)
Voltage,V Current,I Input power, watt
Speed, RPM
0.8 0.02 0.016 0
1 0.02 0.02 407
1.5 0.02 0.03 670
2 0.02 0.04 1034
2.5 0.03 0.075 1306
3 0.03 0.09 1546
3.5 0.03 0.105 1869
4 0.03 0.12 2135
4.5 0.04 0.18 2425
5 0.04 0.2 2653
5.5 0.05 0.275 2935
6 0.05 0.3 3185
Table A2: Control (with starter)
Voltage,V Current,I Input power, watt
Speed, RPM
1.49 0.03 0.0447 0
1.5 0.03 0.045 785
2 0.03 0.06 1091
2.5 0.03 0.075 1471
3 0.04 0.12 1785
3.5 0.04 0.14 2087
4 0.04 0.16 2401
4.5 0.05 0.225 2753
5 0.05 0.25 3031
5.5 0.06 0.33 3332
6 0.06 0.36 3610
Table A3: NdFeB(without starter)
Voltage,V Current,I Input power,
watt Speed,
RPM
0.69 0.03 0.0207 0
0.7 0.03 0.021 315
1.1 0.02 0.022 506
1.5 0.03 0.045 785
2 0.03 0.06 1091
2.5 0.03 0.075 1471
3 0.04 0.12 1785
3.5 0.04 0.14 2087
4 0.04 0.16 2401
4.5 0.05 0.225 2753
5 0.05 0.25 3031
5.5 0.06 0.33 3332
6 0.06 0.36 3610
Table A4: NdFeB (With starter)
Voltage,V Current,I Input power, watt
Speed, RPM
1.09 0.02 0.0218 0
1.1 0.02 0.022 506
1.5 0.02 0.03 804
2 0.03 0.06 1127
2.5 0.03 0.075 1474
3 0.03 0.09 1795
3.5 0.04 0.14 2111
4 0.04 0.16 2420
4.5 0.04 0.18 2720
5 0.05 0.25 2995
5.5 0.05 0.275 3265
6 0.06 0.36 3527
Table A5: Ferrite (without starter)
Voltage,V Current,I Input power, watt
Speed, RPM
0.69 0.02 0.0138 0
0.7 0.02 0.014 227
1.1 0.02 0.022 506
1.5 0.02 0.03 804
2 0.03 0.06 1127
2.5 0.03 0.075 1474
3 0.03 0.09 1795
3.5 0.04 0.14 2111
4 0.04 0.16 2420
4.5 0.04 0.18 2720
5 0.05 0.25 2995
5.5 0.05 0.275 3265
6 0.06 0.36 3527
Table A6: Ferrite (with starter)
APPENDIX B
Density, volume, and surface area calculation
Bonded NdFeB Magnet
In order to get the density of each sample, the weight and volume of the sample was determine. So the diameter and thickness must be measured to get the volume of the sample.
Density, ρ = m/V ; V = πr2h m = mass
V = Volume r = radius h = thickness
5wt% of binder:
Volume, V = π x (12/2)2 x 4.00mm = 452.39 mm3
Density, ρ = x X
= 5.946 g/cc
Surface area= [π62 x2] + [2π6 x 4]
=376mm2
Theoretical density calculation:
ρNd = 7.4 g/cc ρepoxy = 1.3 g/cc ρ = m/V
For 5wt%:
ρmix = (mNd + mepoxy ) ; mNd = ρNd x VT
mepoxy = ρepoxy x VT
ρmix = (0.97x ρNd + 0.03 ρepoxy) VT
VT
2.69gram 452.39 mm3
1000 mm3 1 cc
VT
= 7.21 g/cc
For Ferrite Magnet Weight : 2.891g Volume =
360 15 90 2 ]
3 5 .
[16 − 2X X Π
= 536.77mm3
Density = (2.891g / 536.77mm3 ) x (1000mm3/1cc)
=5.385g/cc
Surface area = (2π9.752 + 2π8.252) /4 + (3x 2x 15)
= 565.16mm2
APPENDIX C
Speed Increment Calculation At 0.15 watt
NdFeB magnet DC motor speed = 2550rpm Ferrite magnet DC motor speed = 1850 rpm
%increment = (2550-1850) / 1850 (x 100%)
= 37%
At 0.2 watt
NdFeB magnet DC motor speed = 3425rpm Ferrite magnet DC motor speed = 2450 rpm
%increment = (3425-2450) / 2450 (x 100%) =39%
At 0.25 watt
NdFeB magnet DC motor speed = 4250rpm Ferrite magnet DC motor speed = 3025 rpm
%increment = (4250- 3050) / 3050 (x 100%)
= 39%
==the average of the speed increment value is calculated to be 38.3%
Appendix D Performance of Magnet
F
F
‐1.50
Figure A1: S
Figure A2: S 0E+03‐1.00E+03 Second
Second quad
Second quad
‐8.00E+02
‐6.00E+02
‐4.00E+02
‐2.00E+02 0.00E+00 2.00E+02 4.00E+02 6.00E+02 8.00E+02 1.00E+03 1.20E+03
3‐5.00E+020.00 Quadrant o
drant of NdFe
drant of Ferri 0E+00 5.00E+0 of Ferrite Ma
eB magnet H
ite magnet H 02 1.00E+03 agnet Hyster
Hysterisis lo
Hysterisis loo resis Loop
Ferrite op
op Magnet
Figure
‐8.00
e A3: Second 0E+03‐6.00E+03 Secon
d quadrant o
Figure A4:
‐1 0 1 2 3 4 5 6
3‐4.00E+03‐2.0 nd Quadrant
H
f Ferrite and
BHmax of Nd 1.00E+03 0.00E+00 1.00E+03 2.00E+03 3.00E+03 4.00E+03 5.00E+03 6.00E+03
00E+030.00E+0 t of Ferrite a Hysteresis Lo
d NdFeB ma
dFeB magne 00 2.00E+03 and NdFeB M oop
agnet Hysteri
et Magnet
Ferrite NdFeB
isis loop Magnet
‐1.00
‐4.00
Fig 0E+06 ‐6.00
‐3
‐2
‐1 0 1 2 3
0E+04 ‐2.00E+
Figure A5:
gure A6: Hys
‐2.50
‐2.00
‐1.50
‐1.00
‐5.00 0.00 5.00
0E+05 ‐2.00 BH ma
3.00E+04 2.00E+04 1.00E+04 0.00E+00 1.00E+04 2.00E+04 3.00E+04
+04 0.00E+00 Hysteresis
: BHmax of fe
sterisis loop E+03
E+03 E+03 E+03 E+02 E+00 E+02
0E+05 2.00
xof Ferrite M
0 2.00E+04 s Loop of Fer
errite magne
of ferrite ma E+05
Magnet
4.00E+04 rrite Magnet
t
agnet BH max Magnet
t
Ferrite x Ferrite
t
Magnet