YASKAWA A1000 Technical Manual page 136

5.2 Fault Detection
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 causes the
DC bus capacitor to overcharge
Improper Setting of Speed Search related
parameters (including Speed Search after a
momentary power loss and after a fault restart)
Drive input power voltage is too high
The braking transistor or braking resistor are
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
136
Overtorque Detection 2
oL4
The current has exceeded the value set for Overtorque Detection 2 (L6-05) for longer than the allowable
time (L6-06).
Mechanical Weakening Detection 1
oL5
Overtorque occurred, matching the conditions specified in L6-08.
High Slip Braking oL
oL7
The output frequency stayed constant for longer than the time set in n3-04 during High Slip Braking.
External Digital Operator Connection Fault
The external operator has been disconnected from the drive.
oPr
Note: An oPr fault will occur when all of the following conditions are true:
• Output is interrupted when the operator is disconnected (o2-06 = 1).
• The Run command is assigned to the operator (b1-02 = 0 and LOCAL has been selected).
Overspeed (for Control Mode with PG)
oS
The motor speed feedback exceeded the F1-08 setting.
Overvoltage
Voltage in the DC bus has exceeded the overvoltage detection level.
ov
• 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
• Increase the deceleration time (C1-02, C1-04, C1-06, C1-08).
• Install a dynamic braking resistor or a dynamic braking resistor unit.
• 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 and braking resistor 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.
Connect a braking resistor.
Possible Solution
YASKAWA ELECTRIC TOEP C710616 41B YASKAWA AC Drive - A1000 Quick Start Guide