TROUBLE SHOOTING
7-9
If an alarm code appears pm the LED monitor
1.
“OCn” Over current protection
Problem The inverter output current momentarily exceeded the over current level.
OC1 Over current occurred during acceleration.
OC2 Over current occurred during deceleration.
OC3 Over current occurred when running at a constant speed.
Possible Causes
What to Check and Suggested Measures
1.
The inverter output terminals
were short circuited.
Remove the wires connected to the inverter output terminals
(U, V, and W) and measure the inter phase resistance. Check
if the resistance is too low.
→
Remove the part that short-circuited (including
replacement of the wires, relay terminals and motor).
2.
Ground faults occurred at the
inverter output terminals.
Remove the wires connected to the inverter output terminals
(U, V, and W) and perform a Mugger test.
→
Remove the part that short-circuited (including
replacement of the wires, relay terminals and motor).
3.
Loads were too heavy.
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)
4.
The value set for torque boost
(F09) was too large. F37 = 0,
1, 3, or 4)
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.
5.
The acceleration/deceleration
time was too short.
Check that the motor generates enough torque required during
acceleration/deceleration. That torque is calculated from the
moment of inertia for the load and the acceleration /
deceleration time.
→
Increase the acceleration/deceleration time (F07, F08,
E10, E11, and H54).
→
Enable current limiting (F43).
→
Raise the inverter capacity.
6.
Malfunction caused by noise.
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).
Summary of Contents for MWHE20
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Page 12: ...SPECIFICATION COMPONENT IDENTIFICATION 2 3 C B ...
