Yaskawa F7 Drive User Manual - Manual (Page 138)

Diagnostics & Troubleshooting 6 - 13
Table 6.2 Alarm Displays and Processing (continued)
Digital
Operator Display
Description Cause Corrective Action
OV
DC Bus Overvolt
(Flashing)
DC Bus Overvoltage
The DC bus voltage has exceeded the trip
point.
Default:
208-240Vac: Trip point is 410Vdc
480Vac: Trip point is 820Vdc
Detected when the Drive is in a stopped
condition. E1-01 affects the trip level.
High input voltage at R/L1,
S/L2 and T/L3
Check the input circuit and
reduce the input power to within
specifications.
The deceleration time is set too
short.
Extend the time in C1-02 or other
active decel settings used such as
C1-04, C1-06, C1-08 or C1-09
(time).
Power factor correction
capacitors are being used on the
input or output to the Drive.
Remove the power factor
correction capacitors.
PGO
PG Open
(Flashing)
PG Disconnection (Detection with
Software)
Detected when F1-02 = 3 and A1-02 = 1
or 3.
Detected when no PG (encoder) pulses are
received for a time longer than the setting in
F1-14.
There was a break in the PG
wiring. Fix the broken / disconnected
wiring.
The PG was wired incorrectly. Fix the wiring.
Power wasn’t being supplied to
the PG.
Supply power to the PG properly.
Brake mechanism is
possibly engaged. Check for open circuit when
using brake (motor).
PGO H
PG Open Hardware
<3021>
PG Disconnection (Detection with
Hardware)
Detected when F1-02 = 3 and F1-25 = 1
(PG-T2 or PG-Z2) and / or F1-26 = 1
(PG-Z2) and A1-02 = 1 or 3.
Detected when no PG (encoder) pulses are
received.
There was a break in the PG
wiring. Fix the broken / disconnected
wiring.
The PG was wired incorrectly. Fix the wiring.
Power wasn’t being supplied to
the PG.
Supply power to the PG properly.
Brake mechanism is possibly
engaged Check for open circuit when
using brake (motor).
UL3
Undertorq Det 1
(Flashing)
Undertorque Detection 1
Drive output current < L6-02 for more than
the time set in L6-03 when L6-01 = 5 or 6.
Motor was underloaded.
Ensure the values in L6-02 and
L6-03 are appropriate.
Check application/machine
status to eliminate fault.
UL4
Undertorq Det 2
(Flashing)
Undertorque Detection 2
Drive output current < L6-05 for more than
the time set in L6-06 when L6-04 = 5 or 6.
Motor was underloaded.
Ensure the values in L6-05 and
L6-06 are appropriate.
Check application/machine
status to eliminate fault.
UV
DC Bus Undervolt
(Flashing)
DC Bus Undervoltage
The DC bus voltage is
≤ L2-05.
Default:
208-240Vac: Trip point is 190Vdc
480Vac: Trip point is 380Vdc
Detected while Drive is in a stopped
condition.
Low input voltage was at R/L1,
S/L2 and T/L3.
Check the input circuit and
increase the input power to
within specifications.
The acceleration time was set
too short.
Extend the time in C1-01 or other
active accel settings used such as
C1-03, C1-05, or C1-07 (time).
Voltage fluctuation of the input
power was too large.
Check the input voltage.