Page 226 - CITS - Electrician - Trade Practical

ELECTRICIAN - CITS

EXERCISE 89 : Check small armature winding,

impregnation, baking

Objectives

At the end of this exercise you shall be able to:
• check a rewound armature winding
• impregnate the rewound armature
• bake the rewound armature

Requirements

Tools/Equipments/Instruments Materials
• Trainees kit - 1 No • Insulating varnish - 100ml
• Soldering iron 25W/250V - 1 No • Emery paper - as reqd
• Digital multimeter - 1 No • Thinner - as reqd
• Winding baking oven - 1 No
• External growler - 1 No
• Amarture static balancer - 1 No

Procedure

TASK 1 :
1 Test the rewound armature with an external growler for shorts, open and grounding.
TASK 2:
1 As per the available infrastructure preheat armature as any one of the following steps from 3 to 6

2 Place the armature in baking oven at a temperature and time specified by the varnish/ resin manufacturer (less
than 90degree) and preheat it to remove moisture from the windings and increases the perpetration of the
varnish.

3 Blow hot air for smaller dc armature within a closed chamber with clean air and temperature not more than 90
4 Place the armature on electric heat radiator
5 Heat the armature with carbon filament lamp, without making any contact with windings. Reduce ventilation if
sufficient high temperature is not available.
6 Monitor for a temperature during preheating.

209

CITS : Power - Electrician & Wireman - Exercise 88