The document discusses the investigation of dielectric properties of polyamide enamel filled with micro and nano fillers of silica and alumina. Key findings include: - The nano silica and alumina taken in a 1:1 mixed enamel sample had the highest dipole moment value for temperatures of 50°C at 50Hz compared to other samples. - The nano silica and alumina taken in a 1:1 mixed enamel sample also had the highest internal field value over the temperature range of 50-150°C compared to other samples. - Dielectric properties like insulating resistance, dipole moment, and internal field were studied for polyamide enamel, micro/nano filler mixtures, and compared across temperature

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Corresponding Author: K. Mohanadasse, Department of EEE, St. Joseph’s College of Engineering, Chennai, India.
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Investigation of Dielectric Properties of the Polyamide
Enamel Filled with Micro and Nano Fillers of SIO and AL O2 2 3
Used in Induction Motors to Reduce Harmonics
K. Mohanadasse, C. Sharmeela and D. Edison Selvaraj1 2 3
Department of EEE, St. Joseph’s College of Engineering, Chennai, India1
Department of EEE, A.C.Tech., Anna University, Chennai, India2
Department of EEE, Panimalar Engineering College, Chennai, India3
Abstract: In the recent days, it was found that the nano fillers play an important role on the enhancement of
the properties of the polyamide enamel as additives. The physical, chemical, electrical, thermal and magnetic
properties of the enamel were improved by the addition of the nano fillers to the polyamide enamel. Many
researches were conducted on the study of the properties of the enamel mixed with nano fillers. Only a few
dielectric properties were studied in this research paper. The investigation includes the study of insulating
resistance, dipole moment and internal field of the polyamide enamel, polyamide enamel mixed with micro and
nano fillers of SiO and Al O taken in different proportions. The various parameters were studied and the2 2 3
results were compared with each other. This research shows the peculiar variation of the dipole moment, internal
field and insulating resistance with temperature and frequency for the micro and nano fillers of SiO and Al O2 2 3
taken in different proportions mixed enamel and the standard enamel. It was observed that the Nano silica and
alumina taken in 1:1 mixed enamel sample has the highest value of dipole moment for the temperature of 50°C
at 50 Hz. It was also shown that the Nano silica and alumina taken in 1:1 mixed enamel sample has the highest
value of the internal field when compared to all the samples at the temperature range of 50 to 150°C.
Key words: Micro fillers Nano fillers Silica Alumina Polarization Insulation resistance Internal field
INTRODUCTION all kinds of electrical apparatuses to insulate the
Nano particles possess electrical, electronic, polymers were mostly subjected to tracking [6-9]. The
mechanical, thermal, magnetic, physical, chemical and formation of continuous conducting paths across the
optical properties [1-3]. The nano particles would exhibit surface of the polymeric insulation mainly due to moisture
an electronic behaviour governed by the quantum and surface erosion was known as tracking.
physics and hence they were called as quantum dots.
Nano science was called as the study of phenomena and In general, an insulating material should have
manipulation of materials at atomic, molecular and macro following properties:
molecular scales [3-5]. Nano technology was also
mentioned as the design, characterization, production Dielectric strength should be high.
and applications of structures, systems and Mechanical strength should be as large as possible.
devices by controlling the shape and size at the scale of Fire proofing qualities should be high.
10 m. Volume and surface resistivity should be large.9
Solid insulating materials should have lower dielectric It should have high thermal conductivity.
loss, higher mechanical strength, should be free from Chemical inertness should be as good as possible.
gaseous inclusions, moisture and be resistant to thermal Water proofing quality should be high.
and chemical deterioration. Generally, they were used in It should have low thermal expansion.
conductors. Some of the solid insulating materials such as

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In order to avoid tracking in polymeric insulating
materials, fillers were used. In the recent years, SiO , TiO ,2 2
CNT, ZNO, ZrO , Al O were used as fillers for polymeric2 2 3
insulating materials [9-11]. Fillers can be added in the form
of micro and nano particles. Nano fillers were added to the
polymeric insulation to improve the performance of the
electrical apparatuses.
Nano fillers added to the polymeric insulation would
have the following advantages:
Higher resistance to partial discharge
Enhanced thermal properties
Lacking of erosion resistance
Matching of coefficient of thermal expansion
Thermal conductivity enhancement
Improved mechanical reinforcement
Increased abrasion resistance
Improved life time
In this research paper, some important properties of
polyamide enamel filled with micro and nano fillers of
silica and alumina were discussed. Some of the most Fig. 1: Proposed work
important properties such as dipole moment, internal field
and insulation resistance were discussed for the temperature and frequency. The thickness of the solid
polyamideenamel,polyamideenamelmixedwith micro and sample was 3 mm. The area of the solid sample was 0.133
nano fillers of silica and alumina taken in different mm. The diameter of the sample was 13 mm. The volume
proportions and the results were compared with each of the sample was 0.0004 mm. The block diagram of
other. proposed work was shown in the Figure 1.
Proposed Work: The fabrication of the nano fillers was DipoleMomentoftheEnamelFilledwithMicroandNano
the important work in this research. Ball mill was used for Fillers of Silica and Alumina: The strength of the electric
the fabrication of silica and alumina nano fillers. The micro dipole moment was proportional to the strength of the
powders of silica and alumina were grinded by ball mill for electric field. Dipole moment was used to find the amount
40 hours. Then the prepared powders were subjected to of polarization and the type of polarization occurring in
SEM. SEM was used to augment the particle size of the the insulating materials. Dielectric spectroscopy was used
fillers. The micro and nano powders were mixed to the to find the different dielectric properties of the insulating
enamel in different proportion by the help of ultrasonic materials [12-13]. Dipole moment was calculated as the
vibrator. The liquid enamel sample was converted into product of polarization vector and volume of the sample.
solid enamel sample by the process called as curing The different values of the dipole moment calculated for
[11-13]. Thermal curing method was adopted for this the various samples were given in the Tables 1 - 5. Nano
research.DDM was used as the curing agent. This silica and alumina taken in 1:1 mixed enamel sample has
process was adopted to form the solid sample. Dielectric the highest value of dipole moment for the temperature of
studies were easier for solid samples. So only, the liquid 50? C at 50 Hz when compared to the values of the dipole
sample was converted into solid sample by means of moment for the different samples. The variation of dipole
thermal curing method. Dielectric spectroscopy was used moment with temperature and frequency was peculiar for
to study the dielectric properties of the solid samples. some samples such as micro silica and alumina taken in 3:1
It was used to measure the capacitance, resistance, mixed enamel and as micro silica and alumina taken in 1:1
dissipation factor, quality factor as the function of mixed enamel. Dipole moment = P * Volume.

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Table 1: Dipole moment in C – m at 50°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 2.23 x 10 7.2 x 10 5.64 x 10 4.1 x 10 3.55 x 10 3.4 x 10 3.73 x 1013 14 14 14 13 13 13
Micro silica and alumina (3:1) mixed enamel 2.82 x 10 8.52 x 10 6.32 x 10 4.8 x 10 3.82 x 10 3.8 x 10 7.04 x 1013 14 14 14 13 13 14
Nano silica and alumina (3:1) mixed enamel 1.45 x 10 8.1 x 10 8.76 x 10 7.2 x 10 6.64 x 10 6.52 x 10 3.93 x 1013 14 14 14 14 14 13
Nano silica and alumina (1:3) mixed enamel 9.6 x 10 9.68 x 10 6.76 x 10 4.96 x 10 4.32 x 10 4.2 x 10 4.9 x 1014 14 14 14 14 14 14
Nano silica and alumina (1:1) mixed enamel 2.8 x 10 1.01 x 10 5.88 x 10 7.32 x 10 6.64 x 10 6.6 x 10 6.76 x 1013 13 13 14 14 14 14
Micro silica and alumina (1:3) mixed enamel 7.2 x 10 4.8 x 10 1.28 x 10 4.4 x 10 4.8 x 10 4.8 x 10 6.2 x 1014 14 14 14 14 14 14
Enamel 1.7 x 10 9.2 x 10 7.2 x 10 5.28 x 10 4.6 x 10 4.52 x 10 5.28 x 1013 14 14 14 14 14 14
Table 2: Dipole moment in C – m at 75°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 1.84 x 10 8 x 10 1.77 x 10 7.1 x 10 6.52 x 10 6.44 x 10 6.72 x 1013 14 13 14 14 14 14
Micro silica and alumina (3:1) mixed enamel 2.21 x 10 8.96 x 10 9.32 x 10 7.6 x 10 6.96 x 10 6.84 x 10 7.36 x 1013 14 14 14 14 14 14
Nano silica and alumina (3:1) mixed enamel 1.79 x 10 8.4 x 10 8.88 x 10 7.24 x 10 6.72 x 10 6.6 x 10 7.04 x 1013 14 14 14 14 14 14
Nano silica and alumina (1:3) mixed enamel 1.84 x 10 1.02 x 10 6.92 x 10 8.1 x 10 7.4 x 10 7.3 x 10 7.76 x 1013 13 14 14 14 14 14
Nano silica and alumina (1:1) mixed enamel 2.2 x 10 1.1 x 10 1.81 x 10 7.36 x 10 6.84 x 10 6.68 x 10 6.84 x 1013 13 13 14 14 14 14
Micro silica and alumina (1:3) mixed enamel 1.62 x 10 8.56 x 10 1.81 x 10 6.72 x 10 7.68 x 10 7.68 x 10 6.2 x 1013 14 13 14 14 14 14
Enamel 1.63 x 10 9.12 x 10 7.16 x 10 5.28 x 10 4.6 x 10 4. 52 x 10 5.36 x 1013 14 14 14 14 14 14
Table 3: Dipole moment in C – m at 100°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 1.76 x 10 2 x 10 1.2 x 10 7 x 10 6.52 x 10 6.4 x 10 6.72 x 1013 13 13 14 14 14 14
Micro silica and alumina (3:1) mixed enamel 2.1 x 10 1.52 x 10 9.44 x 10 7.68 x 10 7 x 10 6.9 x 10 7.5 x 1013 13 14 14 14 14 14
Nano silica and alumina (3:1) mixed enamel 1.5 x 10 2 x 10 8.92 x 10 7.24 x 10 6.72 x 10 6.56 x 10 7 x 1013 13 14 14 14 14 14
Nano silica and alumina (1:3) mixed enamel 1.82 x 10 1.65 x 10 1 x 10 8.2 x 10 7.4 x 10 7.2 x 10 8 x 1013 13 13 14 14 14 14
Nano silica and alumina (1:1) mixed enamel 2.3 x 10 1.6 x 10 9.2 x 10 7.4 x 10 6.8 x 10 6.72 x 10 6.92 x 1013 13 14 14 14 14 14
Micro silica and alumina (1:3) mixed enamel 1.76 x 10 2 x 10 9.04 x 10 7.32 x 10 7.72 x 10 7.72 x 10 6.2 x 1013 13 14 14 14 14 14
Enamel 1.83 x 10 9.6 x 10 7.2 x 10 5.2 x 10 4.4 x 10 4.2 x 10 5 x 1013 14 14 14 14 14 14
Table 4: Dipole moment in C – m at 125°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 1.44 x 10 8.2 x 10 5.8 x 10 4.08 x 10 3.51 x 10 3.36 x 10 3.72 x 1013 14 14 14 14 14 14
Micro silica and alumina (3:1) mixed enamel 1.72 x 10 8.8 x 10 6.52 x 10 4.72 x 10 4 x 10 3.93 x 10 4.4 x 1013 14 14 14 14 14 14
Nano silica and alumina (3:1) mixed enamel 1.78 x 10 8.8 x 10 6.08 x 10 4.32 x 10 3.75 x 10 3.57 x 10 4.08 x 1013 14 14 14 14 14 14
Nano silica and alumina (1:3) mixed enamel 1.94 x 10 1.05 x 10 7.32 x 10 5.2 x 10 5.08 x 10 4.28 x 10 5.16 x 1013 13 14 14 14 14 14
Nano silica and alumina (1:1) mixed enamel 2.42 x 10 7.52 x 10 6.12 x 10 4.44 x 10 3.87 x 10 3.78 x 10 4.68 x 1013 14 14 14 14 14 14
Micro silica and alumina (1:3) mixed enamel 1.82 x 10 3.51 x 10 1.26 x 10 4.44 x 10 4.68 x 10 4.72 x 10 6.16 x 1013 14 14 14 13 14 14
Enamel 1.48 x 10 1.07 x 10 7.12 x 10 5.08 x 10 4.32 x 10 4.2 x 10 4.88 x 1013 13 14 14 14 14 14
Table 5: Dipole moment in C – m at 150°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 1.47 x 10 7.8 x 10 5.84 x 10 4.08 x 10 3.51 x 10 3.39 x 10 3.78 x 1013 14 14 14 14 14 14
Micro silica and alumina (3:1) mixed enamel 1.62 x 10 9.6 x 10 6.72 x 10 4.76 x 10 4.04 x 10 4.36 x 10 4.48 x 1013 14 14 14 14 14 14
Nano silica and alumina (3:1) mixed enamel 1.76 x 10 8.44 x 10 6.28 x 10 5.6 x 10 3.81 x 10 4.68 x 10 4.16 x 1013 14 14 14 14 14 14
Nano silica and alumina (1:3) mixed enamel 2.02 x 10 1.02 x 10 7.12 x 10 5.08 x 10 4.56 x 10 4.72 x 10 5.04 x 1013 13 14 14 14 14 14
Nano silica and alumina (1:1) mixed enamel 2.02 x 10 1.13 x 10 6.48 x 10 5.68 x 10 4.08 x 10 4.36 x 10 5.2 x 1013 13 14 14 14 14 14
Micro silica and alumina (1:3) mixed enamel 1.69 x 10 6.56 x 10 1.16 x 10 4.04 x 10 4.68 x 10 4.72 x 10 3.15 x 1013 14 14 14 14 14 14
Enamel 1.74 x 10 9.16 x 10 7.2 x 10 5.08 x 10 4.24 x 10 4.12 x 10 4.76 x 1013 14 14 14 14 14 14

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Internal Field or Local Field of the Enamel Filled with When the frequency increases, the value of the internal
Micro and Nano Fillers of Silica and Alumina: The space filed for all the samples also decreases for 50 to 150°C.
and the time average of the electric field intensity acting At 50 Hz, the micro silica and alumina taken in 3:1 mixed
on a particular molecule were called as local field or enamel was having the highest value of the internal field
internal field. The local field intensity was higher than when compared to other samples for 75°C. Whereas at
the macroscopic intensity. Lorentz method was used 100°C, the nano silica and alumina taken in 1:1 mixed
for finding the internal field for the cubic structure enamel sample was showing the highest value of the
[6-8]. Internal field was found from the formula, E = E internal field when compared to other samples for 50 Hz.i
+ (P / 3 * ). Polarization vector was found by the It was also observed that at 125°C, nano silica ando
formula, P = E * * ( – 1). The relative permittivity of alumina taken in 1:1 mixed enamel sample has the highesto r
the samples were calculated from the formula, = (C * d) value of the internal field for 50 Hz. While for 150°C, ther p
/ ( * A). The value of the parallel capacitance was nano silica and alumina taken in 1:3 mixed enamel sampleo
measured by means of Dielectric Spectroscopy. was having the highest value of the internal field when
where in 1:1 mixed enamel sample has the highest value of the
E – Applied electric field temperature range of 50 to 150°C.
P – Polarization vector The Figure 2 shows the variation of the internal field
– relative permittivity of the sample with frequency for different samples such as enamel,r
C – parallel capacitance enamel mixed with micro and nano fillers of silica andp
The values of the calculated internal field for different that the nano silica and alumina taken in 1:1 mixed enamel
samples such as polyamide enamel, polyamide enamel sample has the highest value of internal field for 50 Hz.
mixed with micro and nano silica and alumina in different Next to that, micro silica and alumina taken in 1:1 mixed
proportions such as 1:1, 1:3 and 3:1 were shown in the enamel sample occupies the second highest value for the
Tables 6 - 10. At 50 Hz, the micro silica and alumina taken internal field at 50 Hz. It was also shown that the micro
in 1:1 mixed enamel was having the highest value of the silica and alumina taken in 1:1 mixed enamel sample has
internal field when compared to other samples for 50°C. the lowest value of the internal field at 1 MHz.
compared to other samples. Nano silica and alumina taken
internal field when compared to all the samples at the
alumina at different proportions for 50°C. It was observed
Table 6: Internal field of the Enamel filled with micro and nano fillers of silica and alumina in V/m at 50°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 21275.7 7088.79 5619.15 4178.37 3737.7 3527.91 3838.71
Micro silica and alumina (3:1) mixed enamel 26814.6 8363.07 6269.61 4541.34 3924.18 3895.32 6550.04
Nano silica and alumina (3:1) mixed enamel 13956.36 7936.83 8587.29 7088.79 6580.41 6467.19 4065.15
Nano silica and alumina (1:3) mixed enamel 9378.72 9434.22 6693.63 4997.55 4407.03 4291.59 4913.19
Nano silica and alumina (1:1) mixed enamel 26673.63 3858.24 5874.45 7226.43 6637.02 6523.8 6693.63
Micro silica and alumina (1:3) mixed enamel 7075.47 4814.4 12246.96 4469.19 4765.56 4772.22 6128.64
Enamel 16257.39 8965.8 7004.43 5280.6 4653.45 4573.53 5280.6
Table 7: Internal field of the Enamel filled with micro and nano fillers of silica and alumina in V/m at 75°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 17590.5 7770.33 16954.47 7004.43 6467.19 6382.83 6637.02
Micro silica and alumina (3:1) mixed enamel 21112.53 8753.79 9095.67 7485.06 6891.21 6777.99 7258.62
Nano silica and alumina (3:1) mixed enamel 17149.83 8101.11 8671.65 7145.4 6637.02 6523.8 6941.16
Nano silica and alumina (1:3) mixed enamel 17670.42 9965.91 6834.6 7936.83 7287.48 7174.26 7626.03
Nano silica and alumina (1:1) mixed enamel 20676.3 9991.44 17319.66 7258.62 6750.24 6608.16 6777.99
Micro silica and alumina (1:3) mixed enamel 15518.13 8366.4 17347.41 6637.02 7569.42 7569.42 6156.39
Enamel 15680.19 8931.39 7061.04 5280.6 4659 4602.39 5364.96

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Table 8: Internal field of the Enamel filled with micro and nano fillers of silica and alumina in V/m at 100°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 16895.64 18619.47 11300.13 6947.82 6467.19 6353.97 6664.77
Micro silica and alumina (3:1) mixed enamel 19721.7 14634.57 9236.64 7569.42 6947.82 6834.6 7371.84
Nano silica and alumina (3:1) mixed enamel 14352.63 19156.71 8756.01 7174.26 6664.77 6523.8 6920.07
Nano silica and alumina (1:3) mixed enamel 17517.24 15963.24 9858.24 8021.19 7342.98 7174.26 7880.22
Nano silica and alumina (1:1) mixed enamel 21953.91 15821.16 8954.7 7342.98 6777.99 6664.77 6863.46
Micro silica and alumina (1:3) mixed enamel 16952.25 19184.46 8869.23 7230.87 7598 7598.28 6156.39
Enamel 17544.99 9494.22 7117.65 5223.99 4489.17 4348.2 4997.55
Table 9: Internal field of the Enamel filled with micro and nano fillers of silica and alumina in V/m at 125°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 14069.58 8078.91 5817.84 4178.37 3642.24 3500.53 3839.89
Micro silica and alumina (3:1) mixed enamel 16615.92 8643.9 6496.05 4772.22 4121.76 4037.4 4489.17
Nano silica and alumina (3:1) mixed enamel 17178.69 8643.9 6072.03 4404.81 3867.57 3697.74 4178.37
Nano silica and alumina (1:3) mixed enamel 18591.72 10226.76 7233.645 5251.74 4573.53 4375.95 5195.13
Nano silica and alumina (1:1) mixed enamel 23112.75 7428.454 6099.78 4545.78 3980.79 3895.32 4743.36
Micro silica and alumina (1:3) mixed enamel 17460.63 3641.13 1527.69 4516.92 4743.36 4772.22 6128.64
Enamel 14380.38 10424.34 7061.04 5139.63 4432.56 4291.59 4940.94
Table 10: Internal field of the Enamel filled with micro and nano fillers of silica and alumina in V/m at 150°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 14239.41 7682.64 5845.59 4206.12 3641.13 3527.91 3895.32
Micro silica and alumina (3:1) mixed enamel 15623.58 9378.72 6664.77 4827.72 4149.51 4461.42 4573.53
Nano silica and alumina (3:1) mixed enamel 16895.61 8305.35 6241.86 5620.26 3924.18 4744.47 4263.84
Nano silica and alumina (1:3) mixed enamel 19439.76 10029.18 7061.04 5110.77 4655.67 4801.08 5083.02
Nano silica and alumina (1:1) mixed enamel 19410.9 11045.94 6439.44 5704.62 4178.37 4461.42 2553.58
Micro silica and alumina (1:3) mixed enamel 16302.9 6524.91 1432.23 4150.62 4744.47 4772.22 3302.58
Enamel 16698.06 8954.7 7117.65 5111.88 4348.2 4207.23 4828.83
Fig. 2: Variation of the internal field with frequency for different samples at 50°C

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Fig. 3: Variation of the internal field with frequency for different samples at 75°C
Fig. 4: Variation of the internal field with frequency for different samples at 100°C
At 75°C, Micro silica and alumina taken in 3:1 mixed The variation of internal field for micro silica and
enamel sample has the highest value of internal field for 50 alumina taken in 1:3 mixed enamel sample was peculiar for
Hz whereas the enamel sample has the lowest value of 125°C. It has the minimum value of internal field at 1000 Hz
internal field for the temperature of 75°C at 1 MHz. The for the temperature of 125°C. Nano silica and alumina
variation of the internal field with frequency for different taken in 1:1 mixed enamel sample has the maximum value
samples such as enamel, enamel mixed with micro and of the internal field at 50 Hz for the temperature of 125°C.
nano fillers of silica and alumina at different proportions The variation of the internal field with frequency at 125°C
for 75°C was shown in the Figure 3. was shown in the Figure 5 for different samples such as
The variation of the internal field with frequency for enamel, enamel mixed with micro and nano fillers of silica
different samples such as enamel, enamel mixed with micro and alumina at different proportions.
and nano fillers of silica and alumina at different The variation of the internal field with frequency at
proportions at 100°C was shown in the Figure 4. Nano 150°C was shown in the Figure 6 for different samples
silica and alumina taken in 1:1 mixed enamel sample has such as enamel, enamel mixed with micro and nano
the maximum value of the internal field at 50 Hz for the fillers of silica and alumina at different proportions.
temperature of 100°C. Enamel sample has the minimum When compared to all the samples, Nano silica and
value of internal field for the temperature of 100°C at 1 alumina taken in 1:1 mixed enamel sample has the highest
MHz. value of the internal field at 50 Hz for the temperature

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Fig. 5: Variation of the internal field with frequency for different samples at 125°C
Fig. 6: Variation of the internal field with frequency for different samples at 150°C
range of 50°C to 150°C except 75°C. At 75°C, Micro silica dissipate the heat to the surroundings. Insulation
and alumina taken in 3:1 mixed enamel sample has the resistance was defined as the opposition offered
maximum value of internal field for 50 Hz. It was observed by the insulating materials to the leakage current.
that both the nano alumina and silica fillers have equal The insulating materials were subjected to dielectric
dielectric properties. So that nano fillers of silica and stress in the form of electrostatic forces. The insulation
alumina taken in 1:1 mixed enamel has the highest values resistance should be higher for insulating materials
of the internal field. [10-13]. Insulation resistance of the insulating
Insulation Resistance of the Enamel Filled with Micro and surface resistance. Insulation resistance of the
and Nano Fillers of Silica and Alumina: Resistance insulating materials depends upon temperature, moisture,
dissipates energy in the form of heat. When the resistance voltage and age of the insulator. The satisfactory
of the insulation was high, the dielectric losses would be operation of the electrical apparatuses depends to a great
less. The temperature rise of the insulating material extend upon the properties of the insulating materials
depends upon the rate of generation and dissipation of used. Therefore the proper choice of insulating materials
the heat by it. If the rate of generation was greater than for the electrical apparatuses was of considerable
the rate of dissipation, the temperature goes on rising and importance for the design of electrical apparatuses. Table
vice versa. The sources of heat for the insulating materials 11 – 15 shows the values of insulation resistance
were Core loss, Dielectric losses, Harmonic losses and measured by Dielectric Spectroscopy for different
Copper losses [13]. Insulating material should samples.
materials was of two types such as volume resistance

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Table 11: Insulation Resistance in at 50°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 4.99 x10 10.88 x 10 1.63 x 10 176.65 x10 10.23 x10 879.40 173.233 6 6 3 3
Micro silica and alumina (3:1) mixed enamel 48.25 x 10 18.40 x 10 1.80 x 10 182.26 x10 9.89 x10 722.58 118.386 6 6 3 3
Nano silica and alumina (3:1) mixed enamel 16.92 x 10 12.49 x 10 1.70 x 10 176.36 x10 9.77 x10 583.98 154.626 6 6 3 3
Nano silica and alumina (1:3) mixed enamel 26.70 x 10 9.87 x 10 1.52 x 10 146.77 x10 7.86 x10 542.38 73.606 6 6 3 3
Nano silica and alumina (1:1) mixed enamel 44.30 x 10 9.66 x 10 1.37 x 10 173.38 x10 10.17 x10 626.95 76.376 6 6 3 3
Micro silica and alumina (1:3) mixed enamel 4.24 x 10 1.89 x 10 458.14 x10 433.95 62.99 3.54 1.436 6 3
Enamel 19.73 x 10 16.78 x 10 1.45 x 10 138.69 x10 7.13 x10 512.40 55.446 6 6 3 3
Table 12: Insulation Resistance in at 75°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 88.66 x 10 9.37 x 10 1.65 x 10 180.82 x10 10.2 x10 709.99 218.556 6 6 3 3
Micro silica and alumina (3:1) mixed enamel 20.73 x 10 17.67 x 10 1.79 x 10 171.51 x10 8.97 x10 608.39 124.796 6 6 3 3
Nano silica and alumina (3:1) mixed enamel 4.99 x10 84.91 x 10 1.74 x 10 174.654 x10 9.81 x10 537.06 182.203 6 6 3 3
Nano silica and alumina (1:3) mixed enamel 1.79 x 10 9.29 x 10 1.54 x 10 147.19 x10 8 x10 478.68 29.696 6 6 3 3
Nano silica and alumina (1:1) mixed enamel 23.07 x 10 15.08 x 10 1.04 x 10 170.75 x10 10.01 x10 638.67 75.346 6 6 3 3
Micro silica and alumina (1:3) mixed enamel 5.13 x 10 83.23 x10 279.54 x10 7.05 x10 91.77 3.60 1.646 3 3 3
Enamel 59.37 x 10 15.57 x 10 1.41 x 10 135.55 x10 7.04 x10 519.13 69.366 6 6 3 3
Table 13: Insulation Resistance in at 100°C
Frequency in Hz
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Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 4.99 x10 11.01 x 10 1.74 x 10 183.93 x10 10.32 x10 728.05 172.463 6 6 3 3
Micro silica and alumina (3:1) mixed enamel 3.33 x 10 17.04 x 10 1.72 x 10 167.33 x10 9.13 x10 621.74 121.776 6 6 3 3
Nano silica and alumina (3:1) mixed enamel 41.90 x 10 14.59 x 10 1.74 x 10 184.80 x10 10.05 x10 731.39 146.556 6 6 3 3
Nano silica and alumina (1:3) mixed enamel 16.05 x 10 17.35 x10 1.54 x 10 149.64 x10 8.13 x10 688.45 91.276 3 6 3 3
Nano silica and alumina (1:1) mixed enamel 11 x 10 13.54 x 10 1.33 x 10 175.71 x10 10.03 x10 614.86 69.436 6 6 3 3
Micro silica and alumina (1:3) mixed enamel 4.67 x 10 1.75 x 10 737.17 x10 6.79 x10 93.05 3.79 1.616 6 3 3
Enamel 21.25 x 10 10.39 x 10 1.36 x 10 146.06 x10 7.89 x10 583.50 72.016 6 6 3 3
Table 14: Insulation Resistance in at 125°C
Frequency in Hz
---------------------------------------------------------------------------------------------------------------------------------
Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 4.99 x10 8.55 x 10 1.75 x 10 196.68 x10 10.55 x10 892.42 194.413 6 6 3 3
Micro silica and alumina (3:1) mixed enamel 22.88 x 10 18.16 x 10 1.73 x 10 172.44 x10 9.24 x10 630.95 98.676 6 6 3 3
Nano silica and alumina (3:1) mixed enamel 42.98 x 10 13.89 x 10 17.68 x 10 189.69 x10 10.10 x10 775.02 156.466 6 6 3 3
Nano silica and alumina (1:3) mixed enamel 45.93 x 10 12.42 x 10 1.55 x 10 153.99 x10 8.35 x10 751.98 90.356 6 6 3 3
Nano silica and alumina (1:1) mixed enamel 4.99 x10 14.09 x 10 1.36 x 10 172.04 x10 9.79 x10 611.81 2.723 6 6 3 3
Micro silica and alumina (1:3) mixed enamel 2.35 x 10 4.43 x 10 566.15 x10 2.54 x10 106.33 4.15 1.646 6 3 3
Enamel 22.32 x 10 12.11 x 10 1.43 x 10 158.65 x10 8.56 x10 639.17 54.256 6 6 3 3
Table 15: Insulation Resistance in at 150°C
Frequency in Hz
---------------------------------------------------------------------------------------------------------------------------------
Sample 50 100 1000 10000 100000 1000000 5000000
Micro silica and alumina (1:1) mixed enamel 46.40 x 10 13.09 x 10 1.79 x 10 198.50 x10 10.58 x10 899.28 217.416 6 6 3 3
Micro silica and alumina (3:1) mixed enamel 20.34 x 10 15.80 x 10 1.71 x 10 174.46 x10 9.43 x10 734.11 98.276 6 6 3 3
Nano silica and alumina (3:1) mixed enamel 3.58 x 10 13.20 x 10 1.76 x 10 183.41 x10 10.23 x10 839.29 146.886 6 6 3 3
Nano silica and alumina (1:3) mixed enamel 54.68 x 10 12.49 x 10 1.66 x 10 165.32 x10 9.05 x10 621.31 93.856 6 6 3 3
Nano silica and alumina (1:1) mixed enamel 14.05 x 10 13.73 x 10 1.34 x 10 159.15 x10 9.41 x10 665.27 65.146 6 6 3 3
Micro silica and alumina (1:3) mixed enamel 101.41 1.16 x 10 488.42 x10 4.08 x10 76.77 4.26 1.626 3 3
Enamel 19.22 x 10 17.79 x 10 1.52 x 10 172.87 x10 9.14 x10 775.25 71.506 6 6 3 3

9. MEJSR
9
It was found that the insulating resistance was electrical and mechanical engineers to design new
decreasing with the increase in frequency. When the innovative engineering materials that withstand high
transients in the system have the frequency of the order temperatures with less dielectric losses used in the
of MHz, this kind of insulation will be easily subjected to electrical, communication, electronic devices and so on.
the breakdown due to these transients. The enamel These types of materials could have high performances
and enamel mixed with micro and nano fillers show and hence they can be called as high performance nano
the decreasing insulating resistance due to the increase devices in general. These studies could be extended for
in frequency. At 5 MHz, micro silica and alumina taken in the investigations of the dielectric, thermal, chemical,
1:3 mixed enamel sample shows the lowest value of physical, optical, mechanical and magnetic properties of
insulation resistance as 1.64 for 50°C. whereas micro the insulating materials filled with various nano fillers
silica and alumina taken in 3:1 mixed enamel sample has used in engineering applications.
the highest value of insulation resistance as 48.25 M at
50 Hz. ACKNOWLEDGMENT
It was observed that at 5 MHz, micro silica and
alumina taken in 1:3 mixed enamel sample shows the The authors express their sincere thanks to the
lowest value of insulation resistance as 1.64 for 75°C. Ultimate God, the creator of this universe, their parents,
While micro silica and alumina taken in 1:1 mixed enamel brothers, sisters, friends, relatives, college management,
sample has the highest value of insulation resistance as colleagues, students, technicians, various authors, Indian
88.66 M at 50 Hz. Government, Tamil Nadu Government, IIT Bombay, IIT
It was examined that at 5 MHz, micro silica and Madras, IIT Delhi, College of Engineering, Guindy, Mepco
alumina taken in 1:3 mixed enamel sample shows the Schlenk Engineering College, Panimalar Engineering
lowest value of insulation resistance as 1.61 for 100°C. College, Dhanalakshmi Srinivasan College of Engineering
Whereas nano silica and alumina taken in 3:1 mixed and Technology, Loyola College, AC Tech, Madras
enamel sample has the highest value of insulation University, Aurora Scientific and Technological Institute,
resistance as 41.9 M at 50 Hz. Kamaraj College of Engineering and Technology, Anna
From these researches, it was noted that micro silica University of Technology, Tirunelveli, National
and alumina taken in 1:3 mixed enamel sample has the Engineering College and all the persons who have helped
lowest value of insulation resistance as 1.64 for 100°C at us directly and indirectly for our research work.
5 MHz. While nano silica and alumina taken in 1:3 mixed
enamel sample has the highest value of insulation REFERENCES
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