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Mitsubishi Electric FR-F740-00023 Instruction Manual: Inverter Replacement

F700 series.
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(2) Replacement procedure of the cooling fan when using a heatsink protrusion attachment
When replacing a cooling fan, remove a top cover of the
heatsink protrusion attachment and perform replacement.
After replacing the cooling fan, replace the top cover in the
original position.
(3) 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.
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, fluid 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 293 to perform the life check of the main circuit capacitor.
(4) Relays
To prevent a contact fault, etc., relays must be replaced according to the cumulative number of switching times
(switching life).

Inverter replacement

The inverter can be replaced with the control circuit wiring kept connected. Before replacement, remove the wiring
cover of the inverter.
1) Loosen the two installation screws in both ends of the control circuit terminal block. (These screws cannot be removed.)
Pull down the terminal block from behind the control circuit terminals.
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 mounting screws.
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.
Inspection item
Top cover


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