100
Fault Displays and Meanings
* The ground fault here is one which occurs in the motor wiring while the motor is running.
A ground fault may not be detected in the following cases.
• A ground fault with low resistance which occurs in motor cables or terminals.
• A ground fault occurs when the power is turned ON.
Fault Display
Inverter
Status
Description
Causes and Correc-
tive Actions
Digital
Operator
RUN (Green)
ALARM (Red)
Protective Op-
eration
Output is
turned OFF
and motor
coasts to a
stop.
OC (Overcurrent)
Inverter output current
momentarily exceeded
approx. 200% of rated
current.
(Control power supply
fault)
Voltage fault of control
power supply is detected.
• Short circuit or
grounding at Inverter
output side
• Excessive
load
GD
2
• Extremely
rapid
Acceleration/
Deceleration Time
(constants n16 to
n19)
• Special motor used
• Starting motor during
coasting
• Motor of a capacity
greater than the
Inverter rating has
been started.
• Magnetic
contactor
opened/closed at the
Inverter output side
⇓
Check the cause, and re-
store the operation.
• Cycle
power.
If the fault remains,
replace the Inverter.
Note) Before turning the
power ON again, make
sure that no short-circuit
or ground fault occurs at
the Inverter output.
GF (Ground fault)
*
Ground fault current at
the Inverter output ex-
ceeded Inverter rated cur-
rent.
• Check that motor
insulation has not
deteriorated.
• Check the connection
between Inverter and
motor.
Note) Before turning the
power ON again, make
sure that no short-circuit
or ground fault occurs at
the Inverter output.
OV (Main circuit ov-
ervoltage)
Main circuit DC voltage
exceeded the overvolt-
age detection level be-
cause of excessive
regenerative energy from
the motor.
Detection level:
200 V: Stop at main cir-
cuit DC voltage
below approx.
410 V
400 V: Stops at main cir-
cuit DC voltage
of approx. 820 V
or more
• Insufficient
Deceleration Time
(constants n17 and
n19)
• Lowering
of
negative
load (e.g., elevator)
⇓
• Increase
deceleration
time.