Maintenance and troubleshooting
Sub-assembly Item Inspect for
Primary power path Vacuum interrupter 1.    Cleanliness.
2.    Contact erosion. Note: Perform with 
manual-spring checks.
3.    Vacuum integrity. Note: Perform with 
high-potential tests.
Vacuum interrupter contact resistance 1.    Record contact resistance with contacts 
closed and check at each maintenance 
interval to monitor condition.
Vacuum interrupter operator mechanism Cleanliness 1.    Dirt or foreign material.
Fasteners 1.    Tightness of nuts and other locking 
devices.
Manual-spring check 1.    Smooth operation of manual charging, 
manual closing and manual tripping.
Lubrication 1.    Evidence of excessive wear.
2.    Lubricaion of wear points.
Electrical controls Wiring 1.    Mechanical damage or abrasion.
Terminals and connectors 1.    Tightness and absence of mechanical 
damage.
Close and trip solenoids, anti-pump relay 
and auxiliary switches
1.    Automatic charging.
2.    Close and trip with control power.
High-potential test Primary circuit-to-ground and between 
primary disconnects
1.    60-second withstand 37.5 kV, 45 kV or 
60 kV, 60 Hz (53, 64 or 85 kV dc).
Control circuit-to-ground 1.    60-second withstand 1,125 V, 60 Hz.
Insulation Barriers and all insulating components 1.    Cleanliness.
2.    Cracking, crazing, tracking or other sign 
of deterioration.
Space heaters Space heaters 1.    Correct operation.
Table 7: Periodic maintenance and lubrication tasks
34