YASKAWA GA700 Technical Manual page 355

Code Name
Note:
• The drive detects this fault if the motor speed is more than the value set in F1-08 for longer than F1-09.
• Do a Fault Reset to clear the fault.
• If the drive detects this fault, it will operate the motor as specified by the Stopping Method set in F1-03 [Overspeed Detection
Selection].
Code Name
ov Overvoltage
YASKAWA ELECTRIC SIEP C710617 05F YASKAWA AC Drive GA700 Technical Manual
Causes
The oS detection level is set incorrectly.
Causes
Deceleration time is too short and
regenerative energy is flowing from the
motor into the drive.
The acceleration time is too short.
The braking load is too large.
There are surge voltages in the input
power supply.
The drive output cable or motor is
shorted to ground (the current short to
ground is charging the main circuit
capacitor of the drive through the power
supply).
The speed search-related parameters are
set incorrectly (this fault also occurs
during recovery from momentary power
loss and after Auto Restarts).
The power supply voltage is too high.
The braking resistor or braking resistor
unit wiring is incorrect.
The encoder cable is disconnected or
wired incorrectly.
Electrical interference along the encoder
cable.
Electrical interference caused a drive
malfunction.
The load inertia is set incorrectly.
Possible Solutions
Adjust F1-08 [Overspeed Detection Level] and F1-
09 [Overspeed Detection Delay Time].
Possible Solutions
• Set L3-04 = 1 [Stall Prevention during Decel =
General Purpose].
• Increase the value set in C1-02, C1-04, C1-06,
or C1-08 [Deceleration Time].
• Connect a dynamic braking option to the drive.
• Perform Deceleration Rate Tuning.
• Make sure that sudden drive acceleration does
not cause the fault.
• Increase the value set in C1-01, C1-03, C1-05,
or C1-07 [Acceleration Time].
• Increase the value set in C2-02 [S-Curve Time @
End of Accel].
• Set L3-11 = 1 [Overvoltage Suppression Select
= Enabled].
Connect a dynamic braking option to the drive.
Connect a DC reactor to the drive.
Note:
If you turn the phase advancing capacitors ON
and OFF and use thyristor converters in the
same power supply system, there can be surge
voltages that irregularly increase the input
voltage.
1. Examine the motor main circuit cable,
terminals, and motor terminal box, and then
remove ground faults.
2. Re-energize the drive.
• Examine the settings for all speed search-related
parameters.
• Set b3-19 ≠ 0 [Speed Search Restart Attempts ≠
0 times].
• Adjust b3-03 [Speed Search Deceleration Time].
• Do Stationary Auto-Tuning for Line-to-Line
Resistance and then set b3-24 = 1 [Speed Search
Method Selection = Speed Estimation].
Decrease the power supply voltage to match the
drive rated voltage.
Correct wiring errors in the connection to the
braking resistor or braking resistor unit.
Examine for wiring errors or disconnected wires in
the encoder cable, and repair problems.
Isolate the encoder cable from the drive output line
or a different source of electrical interference.
• Examine the control circuit lines, main circuit
lines, and ground wiring, and decrease the
effects of electrical interference.
• Make sure that a magnetic contactor is not the
source of the electrical interference, then use a
Surge Protective Device if necessary.
• Examine the load inertia settings with KEB,
overvoltage suppression, or stall prevention
during deceleration.
• Adjust L3-25 [Load Inertia Ratio] to match the
qualities of the machine.
6.4 Faults
6
355