Chapter 8 Life Of Inverter Parts; Replacement Of Parts - Mitsubishi Electric FATEC FR-A800 Manual

8
LIFE OF INVERTER PARTS

CHAPTER 8 LIFE OF INVERTER PARTS

8.1

Replacement of parts

The inverter consists of many electronic parts such as semiconductor devices.
The following parts may deteriorate with age because of their structures or physical characteristics,
leading to reduced performance or fault of the inverter. For preventive maintenance, the parts must
be replaced periodically.
For 800 series inverters, use the life check function as a guidance of parts replacement.
(1) Cooling fan
The estimated life of the bearing of the cooling fan used for cooling the heat-generating parts
such as the main circuit semiconductor device is 87600 hours (for the 800 series inverters).
Therefore, the parts including the cooling fan in continuous operation should usually be replaced
once in every 10 years. However, if unusual noise or vibration is found during the inspection, the
cooling fan must be replaced immediately.
The 800 series inverters have a function to set the ON/OFF control of the cooling fan. With the
ON/OFF control setting, the cooling fan life can be longer. Also, a cassette type cooling fan can
be replaced easily.
(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. Note that 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 (for the 800 series inverters).
The capacitors are deteriorated rapidly since a certain time period has passed. Therefore,
perform the inspection at least once in every year (once in every half-year is recommended near
the end of the capacitor's life).
The appearance criteria for inspection are as follows:
1) Case: Check the side and bottom faces for expansion.
2) Sealing plate: Check for a remarkable warp and extreme crack.
3) Explosion-proof valve: Check for remarkable expansion and operation.
4) Check for an external crack, discoloration, and liquid leakage etc. Judge that the
capacitor has reached its life when the measured capacitance of the capacitor
reduced below 85% of the rating.
8.1 Replacement of parts
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