7 PRECAUTIONS FOR MAINTENANCE AND INSPECTION
The inverter is a static unit mainly consisting of semiconductor devices. Daily inspection must be performed to prevent
any fault from occurring due to the adverse effects of the operating environment, such as temperature, humidity, dust,
dirt and vibration, changes in the parts with time, service life, and other factors.
• Precautions for maintenance and inspection
For some short time after the power is switched OFF, a high voltage remains in the smoothing capacitor. When
accessing the inverter for inspection, wait for at least 10 minutes after the power supply has been switched OFF, and
then make sure that the voltage across the main circuit terminals P/+ and N/− of the inverter is not more than 30VDC
using a tester, etc.
7.1 Inspection item
Basically, check for the following faults during operation.
(1) Motor operation fault
(2) Improper installation environment
(3) Cooling system fault
(4) Unusual vibration and noise
(5) Unusual overheat and discoloration
Check the areas inaccessible during operation and requiring periodic inspection.
Consult us for periodic inspection.
1) Check for cooling system fault .............. Clean the air filter, etc.
2) Tightening check and retightening ........ The screws and bolts may become loose due to vibration, temperature
3) Check the conductors and insulating materials for corrosion and damage.
4) Measure insulation resistance.
5) Check and change the cooling fan and relay.
Tighten them according to the specified tightening torque.
(Refer to page 15, 16.)