Yaskawa AC Drive Z1000 User Manual
Page 214
HOA Keypad Display
Fault Name
ov
Overvoltage
Voltage in the DC bus has exceeded the overvoltage detection level.
• For 200 V class drives: approximately 410 V
• For 400 V class drives: approximately 820 V (740 V when E1-01 is less than 400)
Cause
Possible Solution
Deceleration time is too short and regenerative
energy is flowing from the motor into the drive
• Increase the deceleration time (C1-02 and C1-04).
• Set L3-04 to 1 to enable stall prevention during deceleration. Stall Prevention is enabled as the
default setting.
Fast acceleration time causes the motor to
overshoot the speed reference
• Check if sudden drive acceleration triggers an overvoltage alarm.
• Increase the acceleration time.
• Use longer S-curve acceleration and deceleration times.
• Enable the Overvoltage Suppression function (L3-11 = 1).
• Lengthen the S-curve at acceleration end.
Ground fault in the output circuit causes the DC
bus capacitor to overcharge
• Check the motor wiring for ground faults.
• Correct grounding shorts and reapply power.
Improper parameters related to Speed Search
(including Speed Search after a momentary power
loss and after a fault restart)
• Check the settings for Speed Search-related parameters.
• Enable Speed Search restart function (b3-19 greater than or equal to 1 to 10).
• Adjust the current level during Speed Search and the deceleration time (b3-02 and b3-03
respectively).
• Perform Stationary Auto-Tuning for line-to-line resistance and then set b3-14 to 1 to enable Speed
Estimation Speed Search.
Drive input power voltage is too high
• Check the voltage.
• Lower drive input power voltage within the limits listed in the specifications.
Drive fails to operate properly due to noise
interference
• Review the list of possible solutions provided for controlling noise.
• Review the section on handling noise interference and check the control circuit lines, main circuit
lines, and ground wiring.
Load inertia is set incorrectly
• Check the load inertia settings when using KEB, overvoltage suppression, or Stall Prevention
during deceleration.
• Adjust the load inertia ratio in L3-25 to better match the load.
Motor hunting occurs
• Adjust the parameters that control hunting.
• Set the gain for Hunting Prevention (n1-02).
• Adjust the speed feedback detection suppression gain for PM motors (n8-45) and the time constant
for pull-in current (n8-47).
HOA Keypad Display
Fault Name
ov2
Overvoltage 2
Bus voltage is boosted because the motor cable is too long.
Cause
Possible Solution
The wiring is too long
• Shorten the shielded motor cable
• Lower the carrier frequency
• Switch on the internal EMC filter if the power supply has a neutral ground
HOA Keypad Display
Fault Name
PF
Input Phase Loss
Drive input power has an open phase or has a large imbalance of voltage between phases. Detected
when L8-05 is set 1 (enabled).
Cause
Possible Solution
There is phase loss in the drive input power
• Check for wiring errors in the main circuit drive input power.
• Correct the wiring.
There is loose wiring in the drive input power
terminals
• Ensure the terminals are tightened properly.
• Apply the tightening torque as specified in this manual.
Refer to Wire Gauges and Tightening
There is excessive fluctuation in the drive input
power voltage
• Check the voltage from the drive input power.
• Review the possible solutions for stabilizing the drive input power.
There is poor balance between voltage phases
Stabilize drive input power or disable phase loss detection.
5.4 Fault Detection
214
YASKAWA ELECTRIC TOEP C710616 45E YASKAWA AC Drive – Z1000 User Manual