82 
 
 
6.2 Fault Detection 
Table 6.2 Fault Displays, Causes, and Possible Solution 
Output power cable is 
damaged 
Check and replace output power 
cable 
oVA、
oVd、
oVC、 
oVAH、 
oVdH、 
ovCH 
Overvoltage 
(Acceleration, 
Deceleration and 
Constant Speed) 
 
The main circuit DC 
voltage exceeded the 
overvoltage 
detection level 
200V class: 410V 
400 V class: 820 V 
1. Regenerative energy is 
flowing from the motor into 
the drive because the 
deceleration time is too 
short 
2. The motor overshoot the 
speed reference because the 
acceleration time is too short   
3. Excessive braking load 
4. Surge voltage entering 
from the drive input power 
5. Motor short-circuited 
Ground fault current charges 
the drive main circuit 
capacitor.   
6. Improper parameter 
settings for Speed Search 
(including Speed Search 
after a fault restart and after 
a momentary power loss)   
7. Drive input voltage is too 
high   
8. The braking transistor or 
braking resistor are wired 
incorrectly 
9. PG cable is disconnected 
10. PG cable wiring is 
incorrect 
11. PG encoder wiring has 
interference of electrical 
signal 
1. Increase the deceleration time 
settings (C1-01 and C1-03) 
»Install a braking unit   
»Set P3-03 (Stall Prevention during 
Deceleration) to 1 
(Enabled)(default is 1) 
2. Confirm if overvoltage alarm 
oVA or oVC was triggered 
during sudden drive 
acceleration.   
»Increase the acceleration time 
»Use S-curve deceleration and 
acceleration times and increase 
the value set to C2-01 ( S-curve 
at acceleration end )   
3.Thyristor convertor and phase 
advancing capacitor using the 
same input power supply might 
cause a voltage surge 
4. Check the motor power cable, 
relay terminals and motor 
terminal box 
» Correct grounding shorts and 
reapply power 
5. Adjust parameter settings for 
Speed Search (group b3)   
»Proceed Auto-Tuning for line-
to-line resistance   
6. Check the voltage 
»Lower drive input power 
voltage within the range listed in 
the drive specifications