Page 151 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

MODULE 14 : AC & DC Windings

LESSON 86-92 : Winding and insulating materials

Objectives

At the end of this lesson you shall be able to:
• list out the insulating materials used for winding and their applications.

Insulating materials : In winding work, proper selection of insulating materials is an important criterion. The ageing
factor of the insulation of Power equipment and apparatus depends upon many factors, such as temperature,
Power and mechanical stress, vibration, moisture, dirt and chemical reaction.

Materials: The following are the common insulating materials used for winding purposes.
• Leatheroid paper • Pressphan paper
• Triplex paper • Millinex paper
• Micanite paper (mica folium)

• Empire cloth • Glass fibre cloth
• Cotton tape • Empire tape
• Fibre glass tape • Cotton sleeves
• Empire sleeves • Fibre glass sleeves
• PVC sleeves • Bamboo

• Hemp thread • Terylene thread
• Varnish

Winding wires

Objectives: At the end of this lesson you shall be able to:
• list out the winding wires used for winding.

Winding wires : The annealed copper conductors, normally in round shape, are used for winding small and
medium capacity Power machines and equipments. These copper wires are provided with a variety of insulation
as stated below.

• Super-enamelled copper wire (S.E.)
• Single cotton-covered copper wire (S.C.C.)
• Double cotton-covered copper wire (D.C.C.)
• Single silk-covered copper wire (S.S.C.)
• Double silk-covered copper wire (D.S.C.)

• PVC-covered copper winding wire
Generally super-enamelled copper winding wire with medium covering is used for most of the winding applications,
whereas for some special applications super-enamelled copper wire with thick covering may be used.

Field coils and armature of certain DC machines might be wound with super-enamelled, DCC or DSC copper
winding wires.
PVC covered copper winding wire is mainly used for submersible pumps.
The winding wires are available in different sizes and grades of insulation.

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