If An Alarm Code Appears On The Led Monitor; Overcurrent Protection - IMO Jaguar CUB Instruction Manual

6.3 If an alarm code appears on the LED monitor

OCn
[ 1 ]

Overcurrent protection

Problem The inverter output current momentarily exceeded the overcurrent level.
OC1
Overcurrent occurred during acceleration.
OC2 Overcurrent occurred during deceleration.
OC3
Overcurrent occurred when running at a constant speed.
Possible Causes
(1) The inverter output
terminals were
short-circuited.
(2) Ground faults occurred at
the inverter output
terminals.
(3) Loads were too heavy.
(4) The value set for torque
boost (F09) was too large.
(F37 = 0, 1, 3, or 4)
(5) The acceleration/
deceleration time was too
short.
(6) Malfunction caused by
noise
What to Check and Suggested Measures
Remove the wires connected to the inverter output terminals
(U, V, and W) and measure the interphase resistance. Check if
the resistance is too low.
Remove the part that short-circuited (including replacement
of the wires, relay terminals and motor).
Remove the wires connected to the inverter output terminals
(U, V, and W) and perform a Megger test.
Remove the part that short-circuited (including replacement
of the wires, relay terminals and motor).
Measure the motor current with a measuring device, and to
trace the current trend. Therefore, use this information to judge
if the trend is over the calculated load value for your system
design.
If the load is too heavy, decrease it or raise the inverter
capacity.
Trace the current trend and check if there are any sudden
changes in the current.
If there are any sudden changes, make the load variation
smaller or raise the inverter capacity.
Enable current limiting (H12).
Check that the output current decreases and that the motor
does not come to stall if you set a lower value than the current
one for F09.
Lower the value for torque boost (F09) if the motor is not
going to stall.
Check that the motor generates enough torque required during
acceleration/deceleration. That torque is calculated from the
moment of inertia for
acceleration/deceleration time.
Increase the acceleration/deceleration time (F07, F08, E10,
E11, and H54).
Enable current limiting (F43).
Raise the inverter capacity.
Check if noise control measures are appropriate (e.g., correct
grounding and routing of control and main circuit wires).
Implement noise control measures.
Enable the auto-reset function (H04).
6-9
the load and the