Mitsubishi Electric MEsoftstart/I01 Users, Installation & Instruction Manual page 58

ii. Check the Motor size setting (Rated Current% potentiometer) on the HMI panel and confirm that this is correct
according to the manufacturers nameplate. (This setting can also be confirmed on the PC Application).
iii. Adjust the Motor Underload percentage (MULC%) on the PC Application. The default is 10%.
Line voltage
iv. Check the supply voltage levels. Measure all three phases and confirm that the supply voltages are within the limits of
the supply voltage for the soft starter (refer Figure 4).
v. If supply voltage is within limits while the motor is not running, start the motor and monitor the supply voltage while
the motor is running. Measure the supply voltage at the soft starter GRID terminals.
vi. If this error occurs repeatedly and all other checks are done, contact your distributor.
Frequency
i. Check the supply frequency. Measure all three phases and confirm that the supply frequency is within the limits of the
supply frequency for the soft starter (refer 10.1).
ii. If supply frequency is within limits while the motor is not running, start the motor and monitor the supply frequency
while the motor is running. Measure the supply frequency at the soft starter GRID terminals.
iii. If this error occurs repeatedly and all other checks are done, contact your distributor.
Over current (start)
This error occurs during the start ramp.
i. Check the motor nameplate for the full load current specification of the motor and re-check the soft starter continuous
current rating as well as the maximum starting current for the MEsoftstart soft starter.
ii. Confirm that the maximum starting current of the MEsoftstart soft starter for the duty required by the installation, is at
least three times the motor full load current (refer paragraph 1.1.1)
iii. If possible, connect the PC Application to the Modbus RTU connector on the soft starter and read back the configuration
(refer par 82). The PC Application will numerically display the configuration of the soft starter so that it is easy to see
where the problem lies.
iv. Confirm that the 'Rated Current%' potentiometer is set correctly for the size of the motor (refer paragraph 5.2 above).
– If the motor size is wrong, the soft starter will apply an incorrect ramp during start-up.
v. Check the setting of the 'Start current' potentiometer. Turn this potentiometer up to allow for a higher starting current.
A typical start current is between 400% and 200% of the Motor Full Load current.
vi. Check the Normal/Heavy setting – When Heavy duty is selected, the soft starter will limit the starting current.
vii. Confirm that the Normal / Inside Delta switch setting is correct for the installation – When Inside Delta is selected the
soft starter will limit the current to 58% of the required current for the selected motor size.
viii. Confirm that the Start Ramp starting% is not too high for the configured motor size. 60% may be too high for a small
motor especially when wired as inside delta.
ix. If changing the settings does not fix the problem contact your distributor for advice.
Ramp up Time
A trip on Ramp-Up time is an indication that the motor takes too long to start with the Soft starter configuration.
i. Make the 'Start Ramp' longer
58 Basic operation – Core models