6-12
Possible Causes What to Check and Suggested Measures
(2) The screws on the main power
input terminals are loosely
tightened.
Check if the screws on the main power input terminals have become loose.
Î Tighten the terminal screws to the recommended torque.
(3) Interphase voltage unbalance
between three phases was too
large.
Measure the input voltage.
Î Connect an AC reactor (ACR) to lower the voltage unbalance between input
phases.
Î Increase the inverter capacity.
(4) Overload cyclically occurred. Measure the ripple wave of the DC link bus voltage.
Î If the ripple is large, increase the inverter capacity.
(5) Single-phase voltage was input
to the three-phase input
inverter.
Check the inverter type.
Î Apply three-phase power. The FRENIC-MEGA of three-phase input cannot be
driven by single-phase power.
The input phase loss protection can be disabled with the function code H98 (Protection/Maintenance Function).
[ 6 ]
0pl
Output phase loss
Problem Output phase loss occurred.
Possible Causes What to Check and Suggested Measures
(1) Inverter output wires are
broken.
Measure the output current.
Î Replace the output wires.
(2) The motor winding is broken. Measure the output current.
Î Replace the motor.
(3) The terminal screws for
inverter output were not tight
enough.
Check if any screws on the inverter output terminals have become loose.
Î Tighten the terminal screws to the recommended torque.
(4) A single-phase motor has been
connected.
Î Single-phase motors cannot be used. Note that the FRENIC-MEGA only drives
three-phase induction motors.
[ 7 ]
0h1
Heat sink overheat
Problem Temperature around heat sink has risen abnormally.
Possible Causes What to Check and Suggested Measures
(1) Temperature around the
inverter exceeded the inverter's
specification range.
Measure the temperature around the inverter.
Î Lower the temperature around the inverter (e.g., ventilate the panel where the
inverter is mounted).
Check if there is sufficient clearance around the inverter.
Î Change the mounting place to ensure the clearance.
(2) Ventilation path is blocked.
Check if the heat sink is not clogged.
Î Clean the heat sink.
Check the cumulative run time of the cooling fan. Refer to Chapter 3, Section 3.4.6
"Reading maintenance information – Menu #5 "Maintenance Information"."
Î Replace the cooling fan.
Visually check whether the cooling fan rotates normally.
Î Replace the cooling fan.
(3) Cooling fan's airflow volume
decreased due to the service
life expired or failure.
Three-phase 200 V class series inverters with 37 kW or above and three-phase 400
V class series with 75 kW or above are equipped with not only a cooling fan for heat
sink but also an internal air circulation fan. Check the following.
Î Check the connection of the fan power switching connectors "CN R" and
"CN W."
Î Correct the connection. (Refer to "h Switching connectors" in Chapter 2,
Section 2.3.4 "Wiring of main circuit terminals and grounding terminals".
(4) Overload. Measure the output current.
Î Reduce the load (e.g. Use the heat sink overheat early warning (E01 through
E07) or the overload early warning (E34) and reduce the load before the
overload protection is activated.).
Î Decease the motor sound (carrier frequency) (F26).
Î Enable the overload prevention control (H70).
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