Yaskawa AC Drive-P1000 Industrial Fan - Manual (Page 306)

External operator is not properly connected to
the drive
• Check the connection between the operator and the drive.
• Replace the cable if damaged.
• Turn off the drive input power and disconnect the operator. Reconnect the operator and reapply drive
input power.
Digital Operator 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)
• For 600 V class drives: approximately 1040 V
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).
• Install a dynamic braking resistor or a dynamic braking resistor unit.
• 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.
Excessive braking load
The braking torque was too high, causing regenerative energy to charge the DC bus. Reduce the braking
torque, use a dynamic braking option, or lengthen decel time.
Surge voltage entering from the drive input
power
Install a DC link choke.
Note: Voltage surge can result from a thyristor convertor and phase advancing capacitor using
the same input power supply.
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.
The braking transistor or braking resistor are
wired incorrectly
• Check braking transistor and braking resistor wiring for errors.
• Properly rewire the braking resistor device.
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 on page
333 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 AFR time constant (n2-02 and n2-03).
Digital Operator 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 Main Circuit Wire Gauges and
Tightening Torque on page 85 for details.
6.4 Fault Detection
306 YASKAWA SIEP YAIP1U 01B AC Drive - P1000 Technical Manual