PROTECTIVE FUNCTIONS
177
5.3.6 Daily and Periodic Inspection
Interval
Periodic*
A
rea o
f
In
sp
ect
io
n
Inspection
Item
Description
Daily
1 y
ear
2 y
ears
Method
Criterion
Instrument
Surrounding
environment
Check ambient
temperature, humidity,
dust, dirt, etc.
'
Refer to page 11.
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.
G
ener
al
Power
supply
voltage
Check that main
circuit voltage is
normal.
'
Measure voltage
across inverter
terminals L
1
-L
2
-L
3
.
Within
permissible AC
voltage
fluctuation
(see
page 186)
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 L
1
, L
2
,
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 L
1
, L
2
, L
3
↔ +
,
−
, and across
U, V, W
↔
+,
−
with
a meter with a 100
Ω
range.
Refer to page
179.
Analog
meter
Main c
ir
c
uit
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
