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Precautions for Maintenance and Inspection
PROTECTIVE FUNCTIONS
6
Control circuit
Protective circuit
Operation
check
(1) Check
balance
of output
voltages
across
phases
with
inverter
operated
independ
ently.
(2) Perform
sequence
protective
operation
test to
make
sure
there is
no fault in
protective
or display
circuits.
#
#
(1) Measure
voltage
across the
inverter
output
terminals
U-V-W.
(2) Simulate
connection
of inverter
protective
circuit
output
terminals.
(1) Phase-to-
phase
voltage
balance
within 4V
for 200V.
(2) Fault must
occur
because of
sequence.
Digital
multimeter,
rectifier type
voltmeter
Cooling system
Cooling fan
(1) Check for
unusual
vibration
and
noise.
(2) Check for
loose
connectio
n.
#
##
#
(1) Turn by
hand with
power off.
(2) Visual
check.
No unusual
vibration and
noise.
Display
Display
(1) Check for
LED
lamp
blown.
(2) Clean.
#
#
(1) Lamps
indicate
indicator
lamps on
panel.
(2) Clean with
rag.
(1) Check that
lamps are
lit.
Meter
Check that
reading is
normal.
#
Check reading
of meters on
panel.
Must satisfy
specified and
management
values.
Voltmeter,
ammeter,
etc.
Area of
Inspection
Inspection
Item
Description
Interval
Method Criterion Instrument
Customer
Check
Daily
Periodic*
1 year
2 years