Instruction manual

140
Fault Display
Digital
Operator
RUN (Green)
ALARM (Red)
Inverter
Status
Explanation
Causes and
Corrective Actions
EF?
(External fault)
Inverter receives an
external fault input from
control circuit terminal.
EF?
PF
LF
UL3
EF0: External fault
reference through
MEMOBUS
communications
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:
• Main circuit power supply
wiring is connected.
• Power supply voltage
• Terminal screws are
securely tightened.
UL3 (Undertorque detection)
When V/f mode is selected:
The inverter’s output current
was less than the
undertorque detection level
(n118).
When vector mode is
selected:
The output current or output
torque was less than the
detection level
(n097 or n118).
Operation when undertorque
is detected will be
determined by the setting in
n117.
• Check the setting in n118.
• Check the operating
conditions, and remove
the cause.
Check the external circuit
(sequence).
PF
(Main circuit voltage fault)
The main circuit’s DC
voltage oscillated in an
irregular way when not in
regenerative operation.
• Open phase of input
supply
• Occurrence of momentary
power loss
• Excessive fluctuation
in input supply voltage
• Unbalanced line voltage
Check the following:
• Main circuit power
supply wiring is connected.
• Power supply voltage
• Terminal screws are
securely tightened.
Protective
Operation
Output is
shut OFF
and motor
coasts to
a stop.