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MAINTENANCE
Table 2 – Check Points for Periodic Inspection (cont.)
Check
Check Item
Point
Main Circuit
Dust on
surface of
vacuum
interrupter
Insulation
Dust, foreign
Frame and
matter or
Flanges
damage
Control
Auxiliary
Circuits
Switch
Drive unit
Wiring
Insulation
Resistance
Resistance
from main
Measure-
circuit to
ment
ground
Resistance
from control
circuits to
ground
Check Method
Visual inspection.
Visual inspection.
See Electrical Service
Life (Page 22) and
Table 3.
Visual inspection.
Visual inspection.
Tighten using a
screwdriver.
Measure insulation
resistance between
phases, between
electrodes, and
between circuits and
ground. Megger test
at 1000V.
Measure insulation
resistance between
circuits and ground.
Megger test at 500V.
Criteria
Make sure there is no
dust on the surface.
Make sure there is no
dust, foreign matter or
breakage.
Contact wear and
wipe. Make sure there
is no dust.
Check for overheating
and discoloration.
Check for
discoloration and
tightness.
Resistance should be
100MΩ or greater.
Resistance should be
5MΩ or greater.
Page 18
What to do
Wipe with a clean,
dry cloth.
Wipe with a clean,
dry cloth. If
damaged, contact
Toshiba.
Replace if wear or
damage is
excessive. See
(Table 1) for
tightening torque
specifications
Contact factory.
Repair if
disconnected.
Tighten if loose.
See (Table 1) for
tightening torque
specifications.
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. If
necessary, replace
faulty parts.
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