8 Fault Diagnosis
199
Protective
Operation
Output is
turned OFF
and motor
coasts to a
stop.
OL3 (Overtorque detec-
tion)
V/f mode: Inverter output cur-
rent exceeded the preset val-
ue in constant n098.
Vector mode: Motor output
current or torque exceeded
the preset value in constants
n097 and n098.
When overtorque is detect-
ed, Inverter performs opera-
tion according to the preset
setting of constant n096.
• Check
the
driven
machine and correct the
cause of the fault, or
increase the value of
constant n098 up to the
highest value allowed for
the machine.
• Check the load size, V/f
set value, operation pat-
tern, etc. to confirm that
the load is not excessive
under actual operation.
• Refer
to
Carrier Fre-
quency Selection
(n080)14kHz max
on
page 89.
• Check
the
wiring
(increase of current
caused by rare shortcir-
cuit, etc.).
PF (Main circuit voltage
fault)
The main circuit’s DC voltage
oscillated in an irregular way
when not in regenerative op-
eration.
• Open phase of input
supply
• Momentary
power
loss
• Excessive
fluctuation
in
input supply voltage
• Unbalanced line voltage
⇓
Check the following:
• Main circuit power sup-
ply connections
• Power supply voltage
• Terminal
screws:
Loose?
LF (Output open phase)
An open phase occurred in
Inverter output.
• Disconnection in output
cable
• Disconnection in motor
windings
• Loose
output
terminal
screws
⇓
Check the following:
• Disconnection in output
wiring
• Motor
impedance
• Terminal
screws:
Loose?
Fault Display
Inverter
Status
Description
Causes and Corrective
Actions
Digital
Operator
RUN (Green)
ALARM (Red)
