MN04002001E
 
16
 
March 2006
 
Step 5 — Troubleshooting Information
The AC drive has a comprehensive fault diagnostic system that includes several 
different alarms and fault messages. Once a fault is detected, the corresponding 
protective functions will be activated. The following faults are displayed as 
shown on the AC drive digital keypad display. The three most recent faults can be 
read on the digital keypad display by viewing 80.04 through 80.06.
Note: Faults can be cleared by resetting at the keypad or with the Input Terminal.
Common Problems and Solutions
Fault
Name Fault Descriptions Corrective Actions
The AC drive detects an 
abnormal increase in current.
1. Check that the motor horsepower 
corresponds to the AC drive output power.
2. Check the wiring connections between the 
AC drive and motor for possible short 
circuits.
3. Increase the acceleration time (20.08).
4. Check for possible excessive loading 
conditions at the motor.
5. If there are any abnormal conditions when 
operating the AC drive after a short circuit is 
removed, it should be sent back to 
manufacturer.
The AC drive detects that the 
DC bus voltage has exceeded 
its maximum allowable value.
1. Check that the input voltage falls within the 
rated AC drive input voltage.
2. Check for possible voltage transients.
3. Bus over-voltage may also be caused by 
motor regeneration. Either increase the 
deceleration time or add an optional braking 
resistor. 
4. Check whether the required braking power 
is within the specified limits.
The AC drive temperature 
sensor detects excessive heat.
1. Make sure that the ambient temperature 
falls within the specified temperature range.
2. Make sure that the ventilation holes are not 
obstructed.
3. Remove any foreign objects from the 
heatsink and check for possible dirty 
heatsink fins.
4. Provide enough spacing for adequate 
ventilation.
The AC drive detects that the 
DC bus voltage has fallen 
below its minimum value.
Check that the input voltage falls within the 
rated AC drive’s input voltage.
The AC drive detects excessive 
drive output current.
Note: The AC drive can 
withstand up to 150% of the 
rated current for a maximum of 
60 seconds.
1. Check if the motor is overloaded.
2. Reduce the torque compensation setting in 
60.09.
3. Replace the AC drive with one that has a 
higher output capacity (next hp size).
Internal electronic overload trip 1. Check for possible motor overload.
2. Check electronic thermal overload setting.
3. Increase motor capacity.
4. Reduce the current level so that the drive 
output current does not exceed the value set 
by the Motor Rated Current (60.01).
Motor overload. Check the 
parameter settings (70.04 
through 70.06)
1. Reduce the motor load.
2. Adjust the over-torque detection setting to 
an appropriate setting.
 
MN04002001E.fm  Page 16  Thursday, April 13, 2006  11:11 AM