Mitsubishi Electric FR-D720S SC EC Instruction Manual page 479

Maintenance and inspection
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 ambient temperature and operating conditions.
When the inverter is operated in air-conditioned, normal environment conditions, replace the ca-
pacitors about every 10 years.
Judge that the capacitor has reached its life when the measured capacitance of the capacitor re-
duced below 80% of the rating.
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:
● Case: Check the side and bottom faces for expansion
● Sealing plate: Check for remarkable warp and extreme crack.
● Check for external crack, discoloration, fluid leakage, etc.
Relays
To prevent a contact fault, etc., relays must be replaced according to the cumulative number of
switching times (switching life).
FR-D700 SC EC
Inspection
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