instruction manual - BHEL Bhopal

2.10 EARTHING OF ACTIVE PART AND CORE INSULATION TEST
2.10.1 REACTORS
The ground-connection terminals for the reactor active part are located
in a box at the tank end, close to the bottom. Please see fig. 2.8.
The terminal are protected by a cover. The cover can be removed with
the tank oil- filled.
The terminal box contains a terminal block with three terminals.
-The terminal marked CL is connected to the core laminations.
-The terminal marked CC is connected to the core clamps.
-The terminal marked G is connected to ground (the tank).
For the core-insulation test, remove the cover. Disconnect the closing
link that connects the two terminals CL-G. Use perferably 3500 V direct voltage
between CL and CC + G. The tank shall be grounded during the test. The
insulation value after 1 min. test- time shall be minimum 1000 kohms. There
is no general requirement on the insulation level CC-G .
2.10.2 TRANSFORMERS
For checking core insulation incase of transformers refer Fig. 2.9 for
connection details.
2.11 TOUCH-UP PAINTING
2.11.1 PURPOSE
A basic principle at touch-up painting should be to restore a damaged
paint coat on a surface to the same quality and finish as of the surrounding
surface. The touch-up painting should be limited to a surface as small as
possible.
2.11.2 CLEANING
Both damaged and surrounding surface should be cleaned so that all
grease, dust and other impurities will be removed.
2.11.3 GRINDING OF DAMAGES
Large damages and defects are ground by means of a coarse abrasive
paper, e.g. No.100. The surface is then ground with a finer paper in connection
with the damage, e.g. 150 or 180. Damages that are limited to the paint coat
only, should be ground off completely at which glazing can be avoided.
2.11.4 PRIMER PAINTING
Damages on the primer paint and grinding down to the steel surface
should be painted with two coats of anti-corrosive priming paint.
Prepared By Samvet Lahari, Bhopal. Phone- 5277412