Omron SYSDRIVE 3G3MV SERIES User Manual page 250

Maintenance Operations
Fault Fault name and meaning
display
PF (See Main circuit voltage fault
note.) (PF)
The main circuit DC voltage
has oscillated erroneously
when regeneration was not
being performed.
This fault is detected when a
voltage fluctuation greater
than the input open-phase
detection level set in n166
persists for longer than the
input open-phase detection
time set in n167.
LF (See Output open-phase fault
note.) (LF)
An open phase has occurred
at the Inverter's output.
This fault is detected when a
current in any of the Inverter
output phases less than the
output open-phase detection
level set in n168 persists for
longer than the output
open-phase detection time set
in n169.
GF (See Ground fault (GF)
note.)
The ground current at the
Inverter has exceeded
approximately 50% of the
Inverter's rated output current.
SC (See Load short circuit (SC)
note.)
The Inverter output or load is
short-circuited.
8-8
Probable cause and remedy
• Momentary power failure.
→ Either apply countermeasures against momentary power
failures or disable the input open-phase detection.
• Input power supply open phase.
→ Check for and correct any main circuit power supply
disconnections or faulty wiring.
• Excessive input power supply voltage fluctuation or bad line
voltage balance.
→ Check the power supply voltage. Apply measures to
stabilize the power supply, or disable the input
open-phase detection.
• Main circuit capacitor failure.
→ If this fault is occurring frequently and there is no error at
the power supply, replace the Inverter or disable the input
open-phase detection. (Also check the usage time with
the accumulated operating time function.)
• Output cable is disconnected.
→ Check for and correct any output cable disconnections or
faulty wiring.
• Motor winding disconnected.
→ Check the motor's line resistance. If winding is broken,
replace the motor.
• Output terminal screws are loose.
→ Check and tighten the output terminal screws.
• Inverter output transistor open breakdown.
→ Replace the Inverter.
• Motor burnout or insulation damage.
→ Check the motor's insulation resistance. If conducting,
replace the motor.
• Cable is damaged.
→ Check the resistance between the cable and FG. If
conducting, replace the cable.
• Cable and FG floating capacity
→ If the cable is longer than 100 m, lower the carrier
frequency.
→ Apply measures to reduce the floating capacity. Don't use
metal ducts, use a separate cable for each phase,
include an AC reactor in the output side, etc.
• Motor burnout or insulation damage.
→ Check the resistance between the motor phases. If
abnormal, replace the Inverter.
• Cable is damaged.
→ Check the resistance between the cables. If conducting,
replace the cable.
Chapter 8