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Troubleshooting the Drive
6-9
HU High DC bus
voltage
DC bus voltage too high (capacitor
protection).
Check input line voltage; if necessary,
add transformer.
Deceleration time too short. Increase deceleration time
P.002/P.018/P.023 versus Maximum
Speed/Hz (P.004). Install DB option
with resistors.
IPL Input phase loss Voltage ripple on DC bus due to
missing input phase or an imbalance
between phases.
Verify that proper voltage is being
applied to the drive. Check all phases.
LU Low DC bus
voltage
DC bus voltage too low. Line dip too
long (P.042).
Check input voltage, line fuses. If
necessary, add transformer. Check
value of Ride Through Time (P.042),
Line Voltage (H.021, U.018).
Input rectifier diodes defective. Check DC bus voltage. If incorrect,
replace diode set.
nCL Network comm loss Communications with the
AutoMax network have been lost.
Check network cabling from network
master to network option board. Check
that network master is operating
properly.
nId Identification
Request not yet
performed (V/Hz
only)
Drive started but Identification
Result = Zero.
Reset fault. Perform Identification
Request. Restart drive.
OC Overcurrent
(steady state).
Trips between 185
to 200% load
(based on inverter
type current) check
Power Module
rating.
Output phase-to-phase short. Check isolation between each output
line.
Bus voltage line-to-line. Check transistor modules for correct
output. If incorrect, possible board
defect; replace. Possible Hall effect
current sensor defective; replace.
Ground fault. Check isolation between ground and
output terminals. Possible leakage
current sensor defect; replace sensor.
Momentary overload. Check for motor overload; reduce load
on motor.
Bad motor. Check motor for correct operation.
Torque boost / V/Hz too high (V/Hz). Check parameters H.001, H.002,
and/or H.003. Enable Identification
Request (H.020)
Motor unknown to regulator (V/Hz). Check that regulator was updated with
actual motor characteristics via
Identification Request (H.020).
Parameter settings (vector). Check Encoder PPR (U.001), Motor
Poles (U.002), Base Frequency
(U.003), Motor Nameplate Amps
(U.004), Magnetizing Current (U.006),
Speed Regulator Prop. Gain (U.012).
Encoder wired incorrectly, wrong PPR. Check encoder wiring. Perform vector
self-tuning.
OCA Overcurrent (at
acceleration)
Overcurrent condition occurred while
accelerating.
Acceleration time too short.
See OC fault corrective actions.
Increase acceleration time (P.001,
P.017, P.021).
Table 6.3 – List of Fault Codes (Continued)
Code
Fault
Description Fault Cause Corrective Action