Chapter 14 Fault Codes and DescriptionsME300 
 
14-23
ID No.  Display on LCM Keypad  Fault Name  Fault Descriptions 
80 
 
V-phase short circuit 
(Boc) 
V-phase  short  circuit  detected  when  output  wiring 
detection is performed before the drive runs. 
Action and Reset 
Action level  240% of the rated current 
Action time  Immediately act 
Fault treatment parameter  N/A 
Reset method  Manual reset 
Reset condition  Reset in 5 sec. after the fault is cleared. 
Record  Yes 
Cause  Corrective Actions 
Incorrect motor wiring 
Check  if  the  motor’s  internal  wiring  and  the  UVW  wiring  of  the  drive  output 
terminal are correct. 
Short-circuit at motor output due to 
poor insulation wiring. 
Without  considering  the  short  circuits,  check  the  motor  cable  or  replace  the 
cable before turning on the power. 
Check for possible burnout or 
aging insulation of the motor. 
Check  the  motor  insulation  value  with  megger.  Replace  the  motor  if  the 
insulation is poor. 
Malfunction caused by interference 
Verify the wiring of the control circuit and wiring/grounding of the main circuit to 
prevent interference. 
The length of motor cable is too 
long. 
Increase the AC motor drive’s capacity. 
Install AC reactor(s) on the output side (U/V/W). 
Hardware failure 
The Boc occurs due to short circuit or ground fault at the output side of the drive. 
Check for possible short circuits between terminals with the electric meter: 
B1 corresponds to U, V, W; DC- corresponds to U, V, W; 
  corresponds to U, 
V, W. 
If short circuits occur, return to the factory for repair. 
 
ID No.  Display on LCM Keypad  Fault Name  Fault Descriptions 
81 
 
W-phase short circuit 
(Coc) 
W-phase  short  circuit  detected  when  output  wiring 
detection is performed before the drive runs. 
Action and Reset 
Action level  240% of the rated current 
Action time  Immediately act 
Fault treatment parameter  N/A 
Reset method  Manual reset 
Reset condition  Reset in 5 sec. after the fault is cleared. 
Record  Yes 
Cause  Corrective Actions 
Incorrect motor wiring 
Check  if  the  motor’s  internal  wiring  and  the  UVW  wiring  of  the  drive  output 
terminal are correct. 
Short-circuit at motor output due to 
poor insulation wiring. 
Without  considering  the  short  circuits,  check  the  motor  cable  or  replace  the 
cable before turning on the power. 
Check for possible burnout or 
aging insulation of the motor. 
Check  the  motor  insulation  value  with  megger.  Replace  the  motor  if  the 
insulation is poor. 
Malfunction caused by interference 
Verify the wiring of the control circuit and wiring/grounding of the main circuit to 
prevent interference. 
The length of motor cable is too 
long. 
Increase the AC motor drive’s capacity. 
Install AC reactor(s) on the output side (U/V/W). 
Hardware failure 
The Coc occurs due to short circuit or ground fault at the output side of the drive. 
Check for possible short circuits between terminals with the electric meter: 
B1 corresponds to U, V, W; DC- corresponds to U, V, W; 
  corresponds to U, 
V, W. 
If short circuits occur, return to the factory for repair. 
 
ID No.  Display on LCM Keypad  Fault Name  Fault Descriptions 
82 
 
Output phase loss   
U phase (OPL1) 
U phase output phase loss 
Action and Reset 
Action level  Pr.06-47 
Action time 
Pr.06-46 
Pr.06-48: Use the setting value of Pr.06-48 first. If DC braking function activates, 
use that of Pr.06-46.