Page 28
MAINTENANCE
Table 2. Check Points for Inspection (cont’d)
Check Point
Check Item
Check Method
Criteria
What to do
Auxiliary
Switch
Terminals loose
or disconnected
Visual
inspection.
Tighten using a
screwdriver.
Make sure terminals are
not loose or disconnected.
Repair if
disconnected.
Tighten if loose.
See Table 1 for
tightening torques.
Case/contacts
Visual
inspection.
Make sure there is no
damage or warping.
Replace if damaged
or warped.
Control
Circuits
Smooth
movement of
motor charging
mechanism
Energize the
control circuit.
Breaker (motor-operated
type) should charge
quickly and smoothly.
If the circuit fails to
operate, check the
cause and repair.
Terminals loose
or disconnected
Visual
inspection.
Tighten using a
screwdriver.
Make sure terminals are
not loose or disconnected.
Repair if
disconnected.
Tighten if loose.
See Table 1 for
tightening torques.
Insulation
Resistance
Measure-
ment
Meaure main
circuit to ground
Megger test at
1000V.
Resistance should be
500M
Ω
or greater.
Meaure
between main
circuit terminals
Megger test at
1000V.
Resistance should be
100M
Ω
or greater.
Meaure control
circuits to
ground
Megger test at
500V.
Resistance should be
2M
Ω
or greater.
If the insulation
resistance is low,
wipe off the vacuum
interrupter and other
insulation surfaces
with a clean dry
cloth and then
repeat the test.