Mitsubishi Electric MEsoftstart/I00, Users, Installation & Instruction Manual

Page: 103 / 119

103 Protective functions
Fault Message Description Corrective action
3.
Motor Overload
Applicable during RUNNING. An overload current was detected while the
motor is running. This limit is defined by
parameter “Motor Over Load Current” (MOLC)
as described in paragraph 6.4.4. Check the motor current specification
and confirm that the configuration of the
following parameters is correct:

Maximum Starting current

Motor Over load current
4. Motor Underload
Applicable during RUNNING.
An underload current was detected during the
start-up ramp. This limit is defined by parameter
“Motor Under Load Current” (MULC) as
described in paragraph 6.4.4.
The check is intended to protect the motor of
e.g. a pump running dry.
Check the motor and the motor load to
ensure all is in order.
Check the motor current specification
and confirm that the configuration of the
following parameter is correct:
 Motor Under load current
5. Voltage Unbalance A voltage unbalance was detected between the
phases of the supply voltage. This limit is defined
by parameter “Voltage unbalance” as described
in paragraph 6.4.7.
This may be caused by one of the three supply
phases that are not present or a wiring error or
grid supply not being within specification.
Supply voltage unbalance can result in a failure
to start or a noisy rough start.
Monitor the supply voltage to confirm
that all three phases are present and
phases are within the local grid
specification.
Adjust the voltage unbalance limit that
the soft starter will tolerate.
6. SCR Volt Unbalance This fault is detected as part of a self-test during
a soft starter power-up (before the soft starter is
in IDLE mode ready to start the motor).
It is an indication of a failure in the SCR
hardware.
Please contact your local distributor.
7. Motor Over Temperature A high temperature on the motor caused the soft
starter to trip in order to protect the motor.
This limit is defined by parameter “Motor
Maximum Temperature” as described in
paragraph 6.4.5.
This error will auto-correct once the motor
temperature drops below the configured “Motor
re-start temperature” Refer paragraph 6.4.5. Inspect the motor and the load. High
motor temperature may be caused by a
too heavy load, or by a malfunction on
the motor such as a locked rotor.
High temperature can also be caused by
a long starting ramp (refer paragraph
6.4.1).
Fix problems on the motor or load
If this is not the cause of the problem,
select a shorter starting ramp with
possibly a higher starting current (refer
paragraph 6.4.4).
8. Over Voltage
These errors are related to the supply voltage
and frequency being outside the specification for
the soft starter. Monitor the supply voltage and
frequency Confirm that the voltage and
frequency is within the specification for
the model of soft starter that is installed.
Check the label on the soft starter to
confirm that the supply voltage is within
the rating of the soft starter.
9. Under Voltage
10. Frequency Limits exceeded
11. Internal Temp High This message indicates that the measured
temperature inside the soft starter enclosure is
too high. Damage will occur if operation is
continued.
Check to confirm that the fans are
working. Note that the soft starter may
be configured to start the fans always
when the motor is running, or to start
the fans only when the temperature is
rising. (Refer paragraph 6.4.5).
Confirm that air inlets and outlets on the
soft starter and on the motor control
enclosure is not blocked.
Refer paragraph 2.3.3.
12. Heatsink Temp High This message indicates that the measured
temperature on the heatsinks inside the soft
starter is too high. Damage will occur if
operation is continued. Check fans and air flow as above for the
ambient temperature.
Confirm that the configuration regarding
the bypass contactor is correct (refer
paragraph 6.4.1).