Yaskawa P7B Drive Bypass - Manual (Page 192)

Diagnostic & Troubleshooting 6 - 12
OV
DC Bus Overvolt
(Flashing)
DC Bus Overvoltage
208-240VAC: Trip point is
≥
400Vdc
480VAC: Trip point is
≥
800Vdc
High input voltage at R/L1,
S/L2 and T/L3.
Check the input circuit and
reduce the input power to within
specifications.
Extend the time in C1-02.
The deceleration time is set too
short.
Power factor correction
capacitors are being used on the
input to the Drive.
Remove the power factor correc-
tion capacitors.
UL3
Undertorq Det 1
(Flashing)
Undertorque Detection 1
Drive output current < L6-02 for more than
the time set in L6-03 Motor is underloaded.
Ensure the values in
L6-02 and L6-03 are appropriate.
Check application/machine status
to eliminate fault.
UV
DC Bus Undervolt
(Flashing)
DC Bus Undervoltage
The DC bus voltage is
≤
L2-05
208-240VAC: Trip point is
≤
190Vdc
480VAC: Trip point is
≤
380Vdc
Low input voltage at R/L1, S/L2
and T/L3.
Check the input circuit and
increase the input power to
within specifications.
The acceleration time is set too
short.
Extend the time in C1-01.
Voltage fluctuation of the input
power is too large.
Check the input voltage.
UV2
CTL PS Undervolt
Control Power Supply Undervoltage of the
control circuit when running External load connected pulling
down the Drive power supplies.
Cycle power off and on to the
Drive.
Repair or replace the Power PCB/
Gate Drive PCB.
UV3
MC Answerback
Soft Charge Circuit Fault
The pre-charge contactor opened while the
Drive was running.
Contacts on the soft charge
contactor are dirty and the soft
charge contactor does not
function mechanically.
Cycle power off and on to the
Drive.
Check the condition of the soft
charge contactor.
Table 6.2 Alarm Displays and Processing (Continued)
Digital
Operator Display
Description Cause Corrective Action