144
Inspection items
(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 converter 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) Explosion-proof valve: Check for extreme valve expansion, and movement of the value.
4) 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 85% of the rating.
(3) Relays
To prevent a contact fault, etc., relays must be replaced according to the cumulative number of switching times
(switching life).
(4) Fuse inside the converter (160K or higher)
A fuse is used inside the converter. Surrounding air temperature and operating condition affect the life of fuses. When the
converter is used in a normal air-conditioned environment, replace its fuse after about 10 years.
HC2.book 144 ページ ２０１２年１１月１９日 月曜日 午前１０時５２分
