5 Troubleshooting
5
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Er.410: Main circuit undervoltage
Cause Conrming Methods Corrective Action
1. The main power is
unstable or fails.
Check power input specication of servo
drive. Measure RST input voltage on servo
drive side and check whether input voltage
complies with the following specication.
220 V AC drive:
Valid value: 220 to 240 V
Allowed error: -10% to 10% (198 to 264 V)
380V AC drive:
Valid value: 380 to 480 V
Allowed error: -10% to 10% (342 to 528 V)
All the three phases must be measured.
Increase power capacity. For
details, refer to Chapter 1 in the
IS650P User Manual.
2. Instantaneous power
down occurs.
3. Voltage dip occurs during
running.
Check power input voltage and check whether
main power is applied to other devices,
resulting insufcient power capacity and
voltage dip.
4. Phase loss exists: Single-
phase power is applied to
three-phase servo drive.
Check whether main circuit RST wiring is
correct and reliable, and whether phase loss
fault detection (H0A-00) is shielded.
Replace cables and connect main
circuit correctly.
Three phases: R, S, T
Single-phase: L1, L2
5. The servo drive is faulty.
Check whether H0B-26 (bus voltage) is within
the following specication:
220V drive: H0B-26 < 200 V
380 V drive: H0B-26 < 380 V
The fault persists after main circuit is powered
on several times.
Replace the servo drive.
Er.420: Power cable phase loss
Cause Conrming Methods Corrective Action
The RST cables are not
connected well.
Check whether RST cables on servo drive
side and non-servo drive side are in good
condition and connected securely.
Replace cables and connect main
circuit correctly.
2. Single-phase power is
applied to three-phase
servo drive.
Conrm power input specication and actual
input voltage. Check whether input voltage
of each phase of main circuit satises the
following specication:
220 V AC drive:
Valid value: 220 to 240 V
Allowed error: -10% to 10% (198 to 264 V)
380V AC drive:
Valid value: 380 to 480 V
Allowed error: -10% to 10% (342 to 528 V)
All the three phases must be measured..
For servo drive of 0.75 kW (H01-
02 = 5), it can be applied by single-
phase power supply.
If input voltage satises specication
on the left, set H0A-00 = 2 (forbid
faults and warnings).
If input voltage does not satisfy
specication on the left, replace or
adjust power capacity.
3. Three-phase voltage is
unbalanced or voltages of
all three phases are too
low.
4. The servo drive is faulty.
The fault persists after main circuit (R, S, T) is
powered on several times.
Replace the servo drive.