6.4 Fault Detection
286
YASKAWA ELECTRIC SIEP C710616 30B YASKAWA AC Drive T1000A Technical Manual
Excessive braking load.
The braking torque was too high, causing regenerative energy to charge the DC bus. Reduce the braking torque, use a braking
option, or lengthen decel time.
Surge voltage entering from the drive input power.
Install a DC reactor.
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 causing the DC bus
capacitor to overcharge.
• Check the motor wiring for ground faults.
• Correct grounding shorts and turn the power back on.
Improper Setting of Speed Search related parameters.
(Includes 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 enable Speed Estimation Speed Search (b3-24 = 1).
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 is wired incorrectly.
• Check braking transistor wiring for errors.
• Properly rewire the braking resistor device.
PG cable is disconnected.
Reconnect the cable.
PG cable wiring is wrong.
Correct the wiring.
Noise interference along the PG encoder wiring.
Separate the wiring from the source of the noise (often the output lines from the drive).
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 has been set incorrectly.
• Check the load inertia settings when using KEB, overvoltage suppression, or Stall Prevention during deceleration.
• Adjust the load inertia ratio in S6-03 to better match the load.
Braking function is being used in OLV/PM.
Connect a braking resistor.
Motor hunting occurs.
• Adjust the parameters that control hunting.
• Set the gain for Hunting Prevention (n1-02).
• Adjust the AFR time constant 1, 2 (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).
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 = 1 or 4
(enabled).
Cause
Possible Solution
There is phase loss in the drive input power while the
drive is running.
• Check for wiring errors in the main circuit drive input power.
• Correct the wiring.
A Run command is entered while an alarm PF has been
triggered.
Remove the cause of the fault.
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 Torque on page 54
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.
The main circuit capacitors are worn.
• Check the maintenance time for the capacitors (U4-05).
• Replace the capacitor if U4-05 is greater than 90%. For instructions on replacing the capacitor, contact Yaskawa or your nearest
sales representative.
Check for anything problems with the drive input power. If drive input power appears normal but the alarm continues to occur,
replace either the control board or the entire drive. For instructions on replacing the control board, contact Yaskawa or your
nearest sales representative.
Digital Operator Display
Fault Name
PGo
PG Disconnect (for any control modes using a PG option card)
No PG pulses are received for longer than the time set to F1-14.
Cause
Possible Solution
PG cable is disconnected.
Reconnect the cable.
PG cable wiring is wrong.
Correct the wiring.
PG has no power.
Check the power line to the PG encoder.
PG encoder brake is clamped shut.
Ensure the motor brake releases properly.
Digital Operator Display
Fault Name
PGoH
PG Hardware Fault
PG cable is not connected properly.
Cause
Possible Solution
PG cable is disconnected.
Reconnect the cable.
Digital Operator Display
Fault Name
rF
Braking Resistor Fault
The resistance of the braking resistor being used is too low.
Cause
Possible Solution
The proper braking resistor option has not been
installed.
Select the braking resistor option so that fits to the drives braking transistor specification.
Regenerative converter, regenerative unit, or braking
unit is being used.
Disable the braking transistor protection selection (set L8-55 to 1).