TERASAKI AME Series, Instruction Manual

Page: 35 / 40

KRB-5200h
-29-
8.2 Inspection Procedures
In order to keep the intended performance and ensure safety of the ACB, it is necessary to inspect
the ACB at intervals recommended in the previous section.
For details of inspection procedures see the following tables.

Before inspecting the internal mechanism of the ACB, loosen the molded-cover fixing screws
and remove the cover.
When the ACB is equipped with the motor operator, remove the motor operator before
removing the cover.
For procedures for removing and mounting the operator, see [3] Before and After Checking the
Trip Settings , XMD Series Motor Operator - Operating Instructions.
■
General
Inspection item Tool/method Criteria Action/remedy
Looseness of
terminal screws
Try to tighten screws
with screwdriver or
wrench
No looseness

Retighten loose screws to the
torque specified in this manual.
Dust and/or foreign
materials
Visual check
No dust or foreign
materials on ACB

Remove dust or foreign materials
with a cleaner.

Wipe dust or foreign materials with
a clean and dry cloth.
Open/close
operation

Manual operation
with operating
handle or trip
button

Electrical operation
with UVT or SHT
Smooth
ON/OFF/Reset
operation

Replace ACB or, if identified, its
defective parts.
(Consult Terasaki for advice)
Crack, damage, or
discoloration on the
cover or mounting
base
Visual check

No crack or
damage

No discoloration
due to overheat

Replace ACB.
Insulation
resistance
500 V
insulation-resistance
tester
5 M
Ω
or more

If insulation resistance is less than
5 M
Ω
, replace ACB.
■
Main conductors
Inspection item Tool/method Criteria Action/remedy
Roughness of
main-contact
surface

Visual check

Contact-resistance
tester (between I/O
terminals)

No wear and
roughness on
contact surface

No increase in
contact resistance

If internal resistance exceeds its
limit after several times of
open/close operation (see Table
4), polish contact surface with
emery paper.
If polishing does not decrease
internal resistance, replace ACB.
Roughness and/or
wear of arc horn or
arcing contacts
Visual check
Remaining thickness:
approx. 1/3

Polish contact surface to remove
roughness.

If thickness decreased to 1/3 or
less, replace moving or stationary
arc horn or arcing contact.
Looseness of arc
horn or arcing
contact fixing
screws
Try to tighten screws
with screwdriver or
wrench
No looseness

Retighten loose screws.