YASKAWA GA700 Technical Manual page 291

Code Name
Note:
• Detected if the DC bus voltage exceeds the ov detection level while the drive is running.
• The ov detection level is about 410 V when using a 200 V class drive. For a 400 V class drive, the detection level is around 820 V.
• Perform Fault Reset to clear the fault.
Code Name
PF Input Phase Loss
YASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual
Cause
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 faulty.
The encoder cable is improperly wired
or disconnected.
Noise interference along the encoder
cable
A drive malfunction occurred due to
noise.
The load inertia is not set correctly.
The Short Circuit Braking function is
being used in Open Loop Vector Control
for PM.
Motor hunting occurs.
Cause
Phase loss in the drive input power.
There is loose wiring in the drive input
power terminals.
Excessive fluctuation in the drive input
power voltage.
Possible Solution
1. Check the motor main circuit cable, terminals,
and motor terminal box, and eliminate any
ground faults.
2. Restart the drive.
• Check the settings for all speed search related
parameters.
• Set b3-19 ≠ 0 [Number of Speed Search Restarts
≠ 0 times].
• Adjust b3-03 [Speed Search Deceleration Time].
• Perform Stationary Auto-Tuning for Line-to-
Line Resistance and then set b3-24 = 1 [Speed
Search Method Selection = Speed Estimation].
Lower the power supply voltage so that it matches
the drive rated voltage.
Correct any wiring errors in the connections with
the braking resistor or braking resistor unit.
Check for any wiring errors or disconnected wires
in the encoder cable, and fix any problems.
Separate the encoder cable from the source of the
noise such as the drive output line.
• Check the control circuit lines, main circuit
lines, and ground wiring, and minimize the
effects of noise.
• Check whether an electromagnetic contactor is
the noise source, and use Surge Protective
Device if necessary.
• Check the load inertia settings when using KEB,
overvoltage suppression, or stall prevention
during deceleration.
• Adjust L3-25 [Load Inertia Ratio] in accordance
with the machine.
Connect a braking resistor to the drive.
• Adjust the parameters that control hunting.
• Adjust n1-02 [Hunting Prevention Gain Setting].
• Adjust n2-02 [SpdFeedbackDetCtr(AFR)
TimeConst1] and n2-03 [SpdFeedbackDetCtr
(AFR)TimeConst2].
• Adjust n8-45 [Spd Feedback Detect Control
Gain] and n8-47 [Pull-InCurCompensationTime
Const].
Possible Solution
Correct any wiring errors in the main circuit drive
input power.
Properly tighten the terminals according to the
specified tightening torque.
• Check for any problems with the input power.
• Review the possible solutions for stabilizing the
drive input power.
• Take steps to stabilize the power supply.
• Check for any problems with the magnetic
contactor on the main circuit side if no problems
are found with the power supply.
6.4 Fault
6
291