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PROTECTIVE FUNCTIONS
142
5.3.6 Daily and periodic inspection
Interval
Periodic*
Area of
Inspection
Inspection
Item
Description
Daily
1 year
2 years
Method Criterion Instrument
Surrounding
environment
Check ambient
temperature, humidity,
dust, dirt, etc.
'
Refer to page 9.
Ambient
temperature:
-10
°
C to +50
°
C,
non-freezing.
Ambient
humidity: 90%
or less, non-
condensing.
Thermo-
meter,
hygrometer,
recorder
Overall unit
Check for unusual
vibration and noise.
'
Visual and auditory
checks.
No fault.
General
Power
supply
voltage
Check that main
circuit voltage is
normal.
'
Measure voltage
across inverter
terminals R-S-T (L
1
-
L
2
-L
3
).
Within
permissible AC
(DC) voltage
fluctuation
(Refer to
page
149)
Meter,
digital
multimeter
General
(1) Check with megger
(across main
circuit terminals
and ground
terminal).
(2) Check for loose
screws and bolts.
(3) Check for overheat
on each part.
(4) Clean.
'
'
'
'
(1) Disconnect all
cables from
inverter and
measure across
terminals R (L
1
),
S (L
2
), T (L
3
), U,
V, W and ground
terminal with
megger.
(2) Retighten.
(3) Visual check.
(1) 5M
Ω
or
more.
(2), (3) No
fault.
500VDC
class
megger
Conductors,
cables
(1) Check conductors
for distortion.
(2) Check cable
sheaths for
breakage.
'
'
(1), (2) Visual
check.
(1), (2) No
fault.
Terminal
block
Check for damage.
'
Visual check No fault
Inverter
module
Converter
module
Check resistance
across terminals.
'
Disconnect cables
from inverter and
measure across
terminals R, S, T-P,
N (L
1
, L
2
, L
3
-
+, −
),
and across U, V, W-
P (+), N (
−
) with a
meter with a 100
Ω
range.
Refer to page
144.
Analog
meter
Main circuit
Smoothing
capacitor
(1) Check for liquid
leakage.
(2) Check for safety
valve projection
and bulge.
(
3
)
Measure
electrostatic
capacity.
'
'
'
(1), (2) Visual
check.
(3) Measure with
capacity meter.
(1), (2) No
fault.
(3) 85% or more
of rated
capacity.
Capacity
meter
5