YASKAWA A1000 Series Quick Start Manual page 107

Cause
Deceleration time is too short and
regenerative energy is flowing from the
motor into the drive.
Fast acceleration time causes the motor to
overshoot the speed reference.
Excessive braking load.
Surge voltage entering from the drive input
power.
Ground fault in the output circuit causing
the DC bus capacitor to overcharge.
Improper Setting of Speed Search related
parameters. (Includes Speed Search after a
momentary power loss and after a fault
restart.)
Drive input power voltage is too high.
The braking transistor is wired incorrectly.
PG cable is disconnected.
PG cable wiring is wrong.
Noise interference along the PG encoder
wiring.
Drive fails to operate properly due to noise
interference.
Load inertia has been set incorrectly.
Braking function is being used in OLV/PM. Connect a braking resistor.
Motor hunting occurs.
Digital Operator Display
Cause
There is phase loss in the drive input power.
There is loose wiring in the drive input
power terminals.
There is excessive fluctuation in the drive
input power voltage.
There is poor balance between voltage
phases.
YASKAWA ELECTRIC TOEP C710616 21C YASKAWA AC Drive - A1000 Quick Start Guide
Overvoltage
Voltage in the DC bus has exceeded the overvoltage detection level.
ov
• For 200 V class: approximately 410 V
• For 400 V class: approximately 820 V
• Increase the deceleration time (C1-02, C1-04, C1-06, C1-08).
• Install a dynamic braking option.
• Enable stall prevention during deceleration (L3-04 = 1).
Stall Prevention is enabled as the default setting.
• 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.
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.
Install a DC reactor.
Note: Voltage surge can result from a thyristor convertor and phase advancing capacitor using the
same input power supply.
• Check the motor wiring for ground faults.
• Correct grounding shorts and turn the power back on.
• 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 enable Speed Estimation
Speed Search (b3-24 = 1).
• Check the voltage.
• Lower drive input power voltage within the limits listed in the specifications.
• Check braking transistor wiring for errors.
• Properly rewire the braking resistor device.
Reconnect the cable.
Correct the wiring.
Separate the wiring from the source of the noise (often the output lines from the drive).
• 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.
• 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.
• Adjust the parameters that control hunting.
• Set the gain for Hunting Prevention (n1-02).
• Adjust the AFR time constant (n2-02 and n2-03).
• Adjust the speed feedback detection suppression gain for PM motors (n8-45) and the time constant
for pull-in current (n8-47).
Input Phase Loss
PF
Drive input power has an open phase or has a large imbalance of voltage between phases. Detected
when L8-05 = 1 (enabled).
• Check for wiring errors in the main circuit drive input power.
• Correct the wiring.
• Ensure the terminals are tightened properly.
• Apply the tightening torque as specified in this manual.
Torque on page 35
• Check the voltage from the drive input power.
• Review the possible solutions for stabilizing the drive input power.
• Stabilize drive input power or disable phase loss detection.
Possible Solution
Fault Name
Possible Solution
Refer to Wire Gauges and Tightening
5 Troubleshooting
5
107