HOA Keypad Display
Fault Name
The rated current of the motor being used is less
than 5% of the drive rated current
Check the drive and motor capacities.
An output transistor is damaged
If the problem continues, replace the control board or the entire drive. Contact Yaskawa or a Yaskawa
representative for instructions on replacing the control board.
A single-phase motor is being used
The drive cannot operate a single phase motor.
HOA Keypad Display
Fault Name
LF2
Output Current Imbalance
One or more of the phases in the output current are lost.
Cause
Possible Solution
Phase loss has occurred on the output side of the
drive
• Check for faulty wiring or poor connections on the output side of the drive.
• Correct the wiring.
Terminal wires are loose on the output side of the
drive
Apply the tightening torque specified in this manual to fasten the terminals.
and Tightening Torque Specifications on page 62
The output circuit is damaged
If the problem continues, replace the control board or the entire drive. Contact Yaskawa or a Yaskawa
representative for instructions on replacing the control board.
Motor impedance or motor phases are uneven
• Measure the line-to-line resistance for each motor phase. Ensure all values match.
• Replace the motor.
HOA Keypad Display
Fault Name
nSE
Node Setup Error
A terminal assigned to the node setup function closed during run.
Cause
Possible Solution
The node setup terminal closed during run
Stop the drive when using the node setup function.
A Run command was issued while the node setup
function was active
HOA Keypad Display
Fault Name
oC
Overcurrent
Drive sensors detected an output current greater than the specified overcurrent level.
Cause
Possible Solution
The motor has been damaged due to overheating
or the motor insulation is damaged
• Check the insulation resistance.
• Replace the motor.
One of the motor cables has shorted out or there is
a grounding problem
• Check the motor cables.
• Remove the short circuit and reapply power to the drive.
• Check the resistance between the motor cables and the ground terminal .
• Replace damaged cables.
The load is too heavy
• Measure the current flowing into the motor.
• Replace the drive with a larger capacity drive if the current value exceeds the rated current.
• Determine if there is sudden fluctuation in the current level.
• Reduce the load to avoid sudden changes in the current level or switch to a larger drive.
The acceleration or deceleration times are too short
Calculate the torque needed during acceleration relative to the load inertia and the specified
acceleration time. If it is not possible to set the proper amount of torque, make the following changes:
• Increase the acceleration time (C1-01)
• Increase the S-curve characteristics (C2-01 and C2-02)
• Increase the capacity of the drive.
The drive is attempting to operate a specialized
motor or a motor larger than the maximum size
allowed
• Check the motor capacity.
• Ensure that the rated capacity of the drive is greater than or equal to the capacity rating found on
the motor nameplate.
Magnetic contactor (MC) on the output side of the
drive has turned on or off
Set up the operation sequence so the MC does not trip while the drive is outputting current.
V/f setting is not operating as expected
• Check the ratios between the voltage and frequency.
• Lower the voltage if it is too high relative to the frequency.
Excessive torque compensation
• Check the amount of torque compensation.
• Reduce the torque compensation gain (C4-01) until there is no speed loss and less current.
6.4 Fault Detection
YASKAWA ELECTRIC SIEP YAIZ1B 01E YASKAWA AC Drive – Z1000 Bypass Technical Manual
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6
Diagnostics & Troubleshooting
