Chapter 5   Troubleshooting and maintenance 
 5-13  
5.4 Routine and periodic inspection 
To ensure stable and safe operations, check and maintain the inverter at regular 
intervals. 
The table below lists the items to be checked to ensure stable and safe operations. 
Check these items 5 minutes after the “Charge” indicator goes out to prevent injury to 
personnel by residual electric power. 
Checking 
period 
Items Details 
Daily 1Year
Methods Criteria Remedies 
Confirm the 
temperature and 
humidity at the 
machine 
○ 
 
Measure with 
thermometer and 
hygrometer 
according to 
installation notices. 
Temperature: 
 -10 – 40
o
C (14-
120℉) 
Humidity: Below 
95% RH 
Ambient 
conditions 
around the 
machine 
Are there 
inflammable 
materials in the 
vicinity? 
○ 
  Visual check  Keep area clear 
Improve the 
ambient or 
relocate the 
drive to a 
better area. 
Any unusual vibration 
from the machine 
○ 
  Visual, hearing check No vibration  Secure screws
Installation 
and grounding 
of the inverter 
Is the grounding 
resistance correct? 
 
○ 
Measure the 
resistance with a 
multi-tester 
200Vclass: below 
100Ω 
400V class: below 
10Ω 
Improve the 
grounding 
Input power 
voltage 
Is the voltage of the 
main circuit correct? 
○ 
 
Measure the voltage 
with a multi-tester 
Voltage must 
conform with the 
specifications 
Improve input 
voltage 
Are secure parts 
loose? 
 
○ 
Is the terminal base 
damaged? 
 
○ 
External 
terminals and 
internal 
mounting 
screws of the 
inverter 
Visual rust stains 
present? 
 
○ 
Visual check 
Check with a 
screwdriver 
Secure terminals 
and no rust 
Secure or send 
back for repair
Any unusual bends or 
breaks? 
 
○ 
Internal wiring 
of the inverter 
Any damage of the 
wire insulation? 
 
○ 
Visual check  No abnormalities 
Replace or 
send back for 
repair 
Heat sink 
Excessive dust or 
debris 
○ 
  Visual check  No abnormalities 
Clean up 
debris or dust
Excessive conductive 
metal shavings or oil 
sludge 
 
○ 
Printed 
circuit board 
Discolored, 
overheated, or 
burned parts 
 
○ 
Visual check  No abnormalities 
Clean or 
replace the 
circuit board 
Unusual vibration and 
noise 
 
○ 
Visual or hearing 
check 
Replace the 
cooling fan 
Cooling fan 
Excessive dust 
or  debris 
○ 
 Visual check 
No abnormalities 
Clean fan 
Excessive dust 
or  debris 
 
○ 
Visual check  No abnormalities 
Clean 
component 
Power 
component 
Check resistance 
between each 
terminals 
 
○ 
Measure with a 
multi-tester 
No short circuit or 
broken circuit in 
three-phase output
Replace 
power 
component or 
inverter 
Any unusual odor or 
leakage 
○ 
 
Capacitor 
Any deformity or 
protrusion 
○ 
 
Visual check  No abnormalities 
Replace 
capacitor or 
inverter