Annex 5
Preventive Maintenance Schedule for Isolators and Earth Switches
|
S. No. |
Tasks assigned |
Shut Down (SD) Or Without Shut Down (WSD) |
Periodicity |
|
A. |
Operating Mechanism |
|
|
|
Maintenance of |
|
|
|
|
a. |
Linkages including tramsmission gears |
SD |
Yearly |
|
b. |
Stopper bolts |
SD |
Yearly |
|
c. |
Cleaning of auxilary switch contact & greasing with silicon grease |
SD |
Yearly |
|
d. |
Lubrication of operating mechanism, hinges, lock joints on levers, bearings |
SD |
Yearly |
|
e. |
Checking of all mounting bolts for tightness |
WSD |
Yearly |
|
B. |
MAIN CONTACTS |
|
|
|
a. |
Cleaning and lubrication of main controls |
SD |
Yearly |
|
b. |
Alignment |
SD |
Yearly |
|
c. |
Main contact resistance measurement |
SD |
2 Yearly |
|
d. |
Tightness of bolds, Nuts and pins etc. |
SD |
Yearly |
|
e. |
Cleaning of support insulators and checking of insulator cracks, if any |
SD |
Yearly |
|
C. |
EARTH SWTICH |
|
|
|
a. |
Checking and Alignment of earthing blades |
SD |
Yearly |
|
b. |
Cleaning of contacts |
SD |
Yearly |
|
c. |
Contact resistance |
SD |
Yearly |
|
d. |
Operation of earthing switch |
SD |
Yearly |
|
e. |
Checking of aluminium Copper flexible conductor |
SD |
Yearly |
|
f. |
Checking of earth connections of structure and MOM box |
SD |
Yearly |
|
D. |
MARSHALLING BOX |
|
|
|
a. |
Visual check of auxiliary contacts |
SD |
Yearly |
|
b. |
Cleaning and terminal tightness in MOM box |
SD |
Yearly |
|
c. |
Checking of space heaters and illumination |
WSD |
Yearly |
|
d. |
Checking of healthiness of gaskets |
WSD |
Yearly |