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6.2 Daily and Periodic Inspections
Part to
Inspection item
inspect
General
Environment
Check the ambient temperature,
humidity, and dust.
Whole inverter
Check for abnormal vibrations and
noise.
Power supply
Check that the main circuit voltage is
voltage
normal.
Main
General check
(1) Check the ground resistance
circuit
between the main circuit and
ground terminals with a megger.
(2) Check screws and bolts for
loosening.
(3) Check each part for any trace of
overheating.
Connecting
(1) Check the conductors for
conductors and
distortion.
cables
(2) Check the cable insulations for
damage.
Terminal block
Check the terminal blocks for damage.
Inverter circuit and
Check the resistance between
converter circuit
terminals.
(including
resistors)
Smoothing
(1) Check for liquid leak.
capacitor
(2) Check that the relief valve does not
protrude or swell.
Relay
(1) Check that no fluttering sound is
generated during the relay
operation.
(2) Check the contacts for damage.
Control
Operation
(1) While performing a unit operation
and
of the inverter, check the balance
protective
output voltage among the
circuits
individual phases.
(2) Carry out a sequential protection
operation test, and check the
protective and display circuits for
any abnormality.
Cooling
Cooling fan
(1) Check for abnormal vibrations and
system
noise
(2) Check the joints for loosening.
Heat sink
Check for clogging.
Display
Monitor
(1) Check that all LEDs light up
normally.
(2) Clean the monitor.
Meter
Check that meter readings are normal.
Motor
General
(1) Check for abnormal vibrations and
noise.
(2) Check for unusual smells.
Insulation
Check the ground resistance between
resistance
all motor terminals and the ground
terminal with a megger.
*1 The operating life of the smoothing capacitor is under the influence of the ambient temperature. Refer to Section 6.6, "Smoothing-Capacitor Life Curve," as a standard for the operating life until
replacement.
*2 The operating life of the cooling fan varies depending on environmental conditions, including the ambient temperature and dust. Check the status of the cooling-fan operation during daily
inspections.
*3 The standard operating life (number of years or operation cycles) and the data described in Section 6.6, "Smoothing-Capacitor Life Curve," are based on the expected design life, but they do not
indicate the guaranteed life of any parts.
*4 When replacing to the capacitor stored for 3 years or longer, please have shakedown period as below.
Apply 80% of rated voltage for 1 hour.
Increase the voltage to 90% and keep for 1 hour.
Then apply rated voltage for 5 hours.
*5 In case fan is locked by dust or particle, it takes 5 to 10 seconds to restart even after the dust is removed.
Inspection cycle
Periodic
Detail of inspection
Daily
Annua
l
Chapter 6 Maintenance and Inspection
Inspection method
Biennial
See Section 2.1, "Installation."
Check visually and by listening.
Measure the voltage between the main
circuit terminals R, S, and T.
Disconnect all input and output cables
from the inverter's main circuit terminal
block, detach the control circuit terminal
block from the inverter, and remove the
jumper for switching the inverter's internal
filter function. Subsequently, measure the
insulation resistance between the ground
terminal and the jumper connecting all the
following terminals:
R, S, T, U, V, W, P, PD, N, RB, R0, and T0
Retighten loose screws and bolts.
Check visually.
Check visually
Check visually
Remove all cables from the inverter's
main circuit terminal block. Use a
tester (in 1Ω range mode) to measure
the following:
- Resistance between terminals R, S,
and T and terminals P and N
- Resistance between terminals U, V,
and W and terminals P and N
Check visually.
Check by listening.
Check visually.
Measure the voltage between the
cables connected to the main circuit
terminals U, V, and W.
Short-circuit or open the protective
circuit outputs as a simulation.
Turn the fan manually during the
inverter power-off status.
Check visually.
Check visually.
Check visually.
Clean the monitor with a rag.
Check the meter readings on the panel. The
Check vibrations and noise visually, by
listening, and with physical senses.
Check for any unusual smells caused by
overheating or damage.
Remove the cables from the inverter's
main circuit terminals U, V, and W,
connect the motor wires (for three
phases) with one another, and
measure the ground resistance
between the motor wires and the
ground terminal.
6-2
Criterion
Test equipment
The ambient temperature must be
Thermometer,
within -10C to +50C without
hygrometer,
congelation. The ambient humidity
recorder
must be 90% RH or less without
condensation.
There must be no abnormality
found.
The measured voltage must be
Tester, digital
within the allowable tolerance for
multimeter
AC power voltage.
500 VDC class
megger
The measured ground resistance
must be 5M or more.
There must be no abnormality
found.
There must be no abnormality
found.
There must be no abnormality
found.
There must be no abnormality
found.
Analog tester
See
Section
6.5,
"Method
of
Checking the Inverter and Converter
Circuits." Standard operating life of
power module(IGBT,IPM,Diode and
6
Thyristor ) until replacement: 10
cycles of starting and stopping (*3)
There must be no abnormality
Capacitance meter
found.
Target
operating
life
until
replacement: 10 years
(*1) (*3)
There must be no abnormality
found.
There must be no abnormality
found.
The inter-phase voltage balance
Digital multimeter,
must be as follows:
rectifier
200 V class models: 4 V or less
instrument, and
400 V class models: 8 V or less
voltmeter
An
error
must
be
detected
according to the sequence.
The fan must rotate smoothly. There
must be no abnormality found.
Standard
operating
life
until
replacement: 10 years
(*2) (*3)
The heat sink must not be clogged.
The LEDs must light up normally.
readings
must
meet
the
Voltmeter and
standard and control values.
ammeter
There must be no abnormality
found.
There must be no abnormality
found.
500 VDC class
megger
The measured ground resistance
must be 5M or more.
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