YASKAWA E7 Drive User Manual

Diagnostic & Troubleshooting 6 - 7
RR
DynBrk Transistr
Dynamic Braking Transistor
The dynamic braking transistor failed
Shorted dynamic braking
transistor, high DC bus
voltage, defective dynamic
braking resistor
Cycle power off and on to the
Drive
Replace defective dynamic
braking transistor or resistor
Monitor DC bus voltage
UL3
Undertorq Det 1
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
UV1
DC Bus Undervolt
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
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
Remove all control wiring and
test Drive
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
Repair or replace the Power PCB/
Gate Drive PCB
Table 6.1 Fault Displays and Processing
Digital
Operator Display
Description Cause Corrective Action

YASKAWA E7 Drive Specifications

General

Brand	YASKAWA
Model	E7 Drive
Category	Controller
Language	English