Electrical Engineering Experiement

1. 2010
SPARK-KING
Knowledge is NO-WHERE …..
(Engineering Lectures and Engineering Solutions)
vijayraskar2003@yahoo.co.in
vijay.raskar1986@gmail.com
09833066325 / 08796149007
VIJAY BALU RASKAR
BE-Electrical / MBA - Operation
[Engineering Assignments]

2. SPARK-KING ….. Unique solution for Learning. VBR
Experiment No:
Title: Observe development of tracks due to
ageing on different Insulating Materials
Roll No:
Batch:
Date:
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DESIGNED BY, PROF. VIJAY BALU RASKAR

3. SPARK-KING ….. Unique solution for Learning. VBR
EXPERIMENT NO:
OBSERVE DEVELOPMENT OF TRACKS DUE TO
AGEING ON DIFFERENT INSULATING MATERIALS
TITLE: Study of insulating materials like mica, Bakelite, etc
AIM: To study different types and properties of insulating materials with
observation development of tracks due to ageing on different insulating materials.
THEORY: Requirements of good insulating materials:
Before selecting an insulating material for a particular application the
following properties need to be considered.
A] Mechanical Properties
B] Thermal Properties
C] Environmental including chemical Properties
D] Electric Properties
E] Economic Consideration
A] Mechanical Properties: The mechanical properties which are considered are
tensile strength, elongation, tensile modulus, compressive modulus, impact
strength, etc. Best of one property does not mean that material chosen will be the
best. Mechanability niches are important. Low viscosity liquids are used for X’mer
and switchgear. Porosity is another factor for consideration. High porosity
materials will absorb moisture.
B] Thermal Properties: thermal properties include temperature and time of
exposure. In this, what is important is at what temperature one can operate this
device for the required lifetime. Properties of materials change at lower
temperatures. In general, tensile strength, greater elongation, smaller elongation
makes material brittle. Fire is another aspect of thermal problem. The insulating
materials used must be stable within the allowed temperatures. The ability of
temperature to affect important properties like electrical, mechanical etc. has
made thermal properties all the more important. Some of the thermal properties
checked for certain insulating materials are melting point, flash point, volatility,
thermal conductivity, thermal expansion and heat resistance.
C] Environmental Properties including Chemical: Environmental properties
including chemical come in picture as to under what kind of operation must the
device operate in. Environment includes the effect of air, light, U.V rays, acid,
alkalis fumes and humidity.
___________________________________________________
DESIGNED BY, PROF. VIJAY BALU RASKAR

4. SPARK-KING ….. Unique solution for Learning. VBR
- Hydrolysis and oxidation should not occur in the insulating material. They
should be chemically stable and offer resistance to oils, solvents, acids and
alkalis.
- While in use of a material certain chemical changes take place, but its
properties should not change.
-Some insulating materials absorb moisture and this property is called
hygroscopicity.
- Ageing of a material occurs due to the effects of heat and chemical action and
voltage application.
E] Electrical Properties: The actual performance of an electrical circuit is a
function not only of the properties of materials but of geometry also. There is an
exact analogy with the mechanical properties. From the electric function point of
view the most important property is the dielectric strength of the insulation. It is
that value of voltage which causes the rupture of the insulating material in
practical use. Another important property is the dielectric constant which
determines the share of electric stress which is absorbed by the material.
Economic may or may not be an important factor for a given application. A good
insulating material should have a low dissipation factor, high insulation resistance
and good dielectric strength and high mechanical strength. They should have
high thermal strength. A good insulating material should have a low permittivity
and giving high discharge stress, free from gaseous insulation to avoid
discharges.
NOTE:- Stick color pictures of the following insulating materials and write
it’s Application and Properties.
1. Bakelite
2. Perspex
3. Mica
4. Micanite
5. Fiberglass
Also, add few points based on old insulating material problems and
disadvantages.
Stick insulating material picture from life (Home, Industry etc)
___________________________________________________
DESIGNED BY, PROF. VIJAY BALU RASKAR

5. SPARK-KING ….. Unique solution for Learning. VBR
RESULT:-
We understand the different insulating material and observed
development of tracks due to ageing on different insulating materials.
CONCLUSION:-
Thus, we studied different insulating materials properties and its application.
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DESIGNED BY, PROF. VIJAY BALU RASKAR