Chapter 8 - Troubleshooting & Maintenance
188
8.6 Daily and Periodic Inspection Items
Period
Inspection
Location
Inspection
Item
Inspection
Daily
1 year
2 year
Inspection Method
Criterion
Measuring
Instrument
Ambient
Environ-
ment
Is there any dust?
Is the ambient temperature and humidity
adequate?
Ο
Refer to the precautions .
Temperature:
-10~+40 no
freezing.
Humidity: Under
50% no dew
Thermometer
,
Hygrometer,
Recorder
Equipment Is there any abnormal oscillation or noise?
Ο
Use sight and hearing.
No abnormality
All
Input
Voltage
Is the input voltage of the main circuit
normal?
Ο
Measure the voltage between the
terminals R, S, T.
Digital Multi-
Meter/Tester
All
Megger check (between the main circuit and
the ground)
Are any fixed parts removed?
Are there any traces of overheating at each
component’s cleaning?
Ο
Ο
Ο
Ο
Undo the inverter connections short
the terminals R, S, T, U, V, W and
measure between these parts and the
ground.
Tighten the screws.
Visual check.
Over 5M
Ω
No fault
DC 500V
class Megger
Conductor/
Wire
Is the conductor rusty?
Is the wire coating damaged?
Ο
Ο
Visual check
No fault
Terminal
Is there any damage?
Ο
Visual check
No fault
IGBT
Module
/Diode
Module
Check the resistance between each of the
terminals.
Ο
Undo the inverter connection and
measure the resistance between R, S,
T
⇔
P, N and U, V, W
⇔
P, N with a
tester.
(Refer ‘How to
Check Power
Components”)
Digital Multi-
Meter/Analog
Tester
Smoothing
Capacitor
Is there any liquid coming out?
Is the safety pin out, and is there any
swelling?
Measure the capacitance.
Ο
Ο
Ο
Visual check
Measure with a capacitance-
measuring device.
No fault
Over 85% of the
rated capacity
Capacitance
Measuring
Device
Relay
Is there any chattering noise during
operation?
Is there any damage to the contact
Ο
Ο
Auditory check
Visual check
No fault
Main
C
ircuit
Resistor
Is there any damage to the resistor
insulation?
Is the wiring in the resistor damaged (open)?
Ο
Ο
Visual check
Disconnect one of the connections
and measure with a tester.
No fault
Error must be
within
±
10% the
displayed
resistance.
Digital Multi-
Meter/Analog
Tester
Control
C
ircuit
Protective
C
ircuit
Operation
Check
Is there any unbalance between each
phases of the output voltage?
Nothing must be wrong with display circuit
after executing the sequence protective
operation.
Ο
Ο
Measure the voltage between the
output terminals U, V and W.
Short and open the inverter protective
circuit output.
The voltage
balance between
the phases for
200V (800V) class
is under 4V (8V).
The fault circuit
operates according
to the sequence.
Digital Multi-
Meter/Rectifyi
ng Voltmeter
Cooling
System
Cooling
Fan
Is there any abnormal oscillation or noise?
Is the connection area loose?
Ο
Ο
Turn OFF the power and turn the fan
by hand.
Tighten the connections.
Must rotate
smoothly.
No fault
Display
Meter
Is the displayed value correct?
Ο
Ο
Check the meter reading at the
exterior of the panel.
Check the
specified and
management
values .
Voltmeter/
Ammeter etc.
All
Are there any abnormal vibrations or noise?
Is there any unusual odor?
Ο
Ο
Auditory , sensory, visual check.
Check for overheat and damage.
No fault
Motor
Insulation
Resistor
Megger check (between the output terminals
and the ground terminal)
Ο
Undo the U, V and W connections and
tie the motor wiring.
Over 5M
Ω
500V class
Megger
☞
Note:
Values in ( ) is for the 400V class inverters.
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