Omron SYSDRIVE 3G3MV User Manual page 263

Maintenance Operations
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.
BUS Communications error
(Option Unit)
A communications error
occurred at the Option Unit.
Note This fault is displayed for 200 and 400-V, 5.5-/7.5-kW Inverters only.
8-10
· 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.
· Communications cable wired incorrectly, short-circuited, or
disconnected.
® Check and correct the communications cable wiring.
· Data destroyed by noise.
® Change to a dedicated communications cable or to
shielded cable, and mask the shield or ground it at the
power supply.
® Use a dedicated communications power supply, and
connect a noise filter to the power supply input side.
· Option Unit is damaged.
® If communications errors frequently occur and there is no
problem with the wiring, replace the Option Unit.
Chapter 8