(2) Smoothing capacitors
A large-capacity aluminum electrolytic capacitor is used for smoothing in the main circuit DC section, and an aluminum
electrolytic capacitor is used for stabilizing the control power in the control circuit. Their characteristics are deteriorated by the
adverse effects of ripple currents, etc. The replacement intervals greatly vary with the surrounding air temperature and
operating conditions. When the inverter is operated in air-conditioned, normal environment conditions, replace the capacitors
about every 10 years.
When a certain period of time has elapsed, the capacitors will deteriorate more rapidly. Check the capacitors at least every
year (less than six months if the life will be expired soon).
The appearance criteria for inspection are as follows:
1) Case: Check the side and bottom faces for expansion
2) Sealing plate: Check for remarkable warp and extreme crack.
3) Check for external crack, discoloration, liquid leakage, etc. Judge that the capacitor has reached its life when the
measured capacitance of the capacitor reduced below 80% of the rating.
Refer to page 120 to perform the life check of the main circuit capacitor.
To prevent a contact fault, etc., relays must be replaced according to the cumulative number of switching times (switching life).
The inverter can be replaced with the control circuit wiring kept connected. Before replacement, remove the wiring cover of
(1) Remove the installation screw of the control circuit terminal block.
Pull the control circuit terminal downward.
(2) Using care not to bend the pins of the inverter's control circuit connector, reinstall the control circuit terminal block and fix
it with the installation screw.
Before starting inverter replacement, switch power OFF, wait for at least 10 minutes, and then check the voltage with
a tester and such to ensure safety.