Page 141 - WCS - Electrical

WORKSHOP CALCULATION & SCIENCE - CITS

• Nitrite butadience rubber

• Butyl rubber
• Hypalon rubber
• Neoprene rubber
• Silicon rubber

S.No Name Properties Uses

Good resilience, wear resistance,
flexibility at low temperature,
Nitrite butadiene
1 resistance to ageing, oxidation, Automobile tyre inner tubes.
rubber
low tensile strength, high thermal
conductivity, low hygroscopicity

It is attacked by petroleum oils, Used as insulation in hot and
gases and alcoholic solvents. It has
2 Butyl wet conditions, used as tapes in
thermal and oxidation stability and repair work.
high resistance to ozone.
Resistance to deterioration
3 Hypalon rubber when exposed to sunlight and Used in jacketing of electric
wires and cables
temperature (up to 150°C).
Better resistance to ageing,
oxidation and gas diffusion, better
4 Neoprene rubber thermal conductivity and flame Used for wire insulation and
cable sheating.
resistance, poor mechanical
properties.

High operating temperature (200°C) Insulation for power cables and
flexibility, moisture and corrosion control wires of blast furnace
resistance, resistance to oxidation, coke ovens, steel mills and
5 Silicon
ozone, arcing, good insulating nuclear power stations high
properties and thermal conductivity. frequency generators, boiler,
It is a good insulator. airport lighting cranes.

Properties and uses of timber
General properties
Timber should have the following properties

• Straight fibres.
• Silky lustre when planed.
• Uniform colour.
• Regular annual rings.
• Heaviness.

• Firm adhesion of fiber and compact modulary rays.
• Sweet smell.
• It should be free from loose or dead knots and shakes.
• The surface should not clog the teeth of the saw on cutting but should remain bright.

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CITS : WCS - Electrical - Exercise 11