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Oscillation or Hunting
Cause
Possible Solutions
Insufficient tuning in Open Loop Vector Control
Adjust the following parameters in the order listed.
An increase in gain should be followed with an increase in the primary delay time constant.
• C4-02 (Torque Compensation Primary Delay Time)
• n2-01 (Speed Feedback Detection Control [AFR] Time Constant 1)
• C3-02 (Slip Compensation Primary Delay Time)
The response for torque compensation and slip compensation will drop as the time constant is
increased.
Auto-Tuning has not yet been performed (required for
Open Loop Vector Control).
Perform Auto-Tuning.
Set motor parameters after calculating the proper values.
Change the motor control method to V/f Control (A1-02 = “0”).
Insufficient tuning in V/f Control.
Reduce the gain.
• n1-02 (Hunting Prevention Gain Setting)
• n1-03 (Hunting Prevention Time Constant Setting)
Gain is too low when using PID control.
Check the period of oscillation and adjust P, I, and D settings accordingly.
The frequency reference is assigned to an external
source and the signal is noisy.
• Ensure that noise is not affecting the signal lines.
• Separate main circuit wiring and control circuit wiring.
• Use twisted-pair cables or shielded wiring for the control circuit.
• Increase the analog input time filter constant (H3-13).
The cable between the drive and motor is too long.
• Perform Auto-Tuning.
• Reduce the length of the cable.
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PID Output Fault
Cause
Possible Solutions
No PID feedback input.
• Check the multi-function analog input terminal settings.
• Set multi-function analog input terminal A1 or A2 for PID feedback (H3-02 or H3-10 = “B”).
• A signal input to the terminal selection for PID feedback is necessary.
• Check the connection of the feedback signal.
• Check the various PID-related parameter settings.
• No PID feedback input to the terminal causes the value detected to be 0, causing a PID fault
and the drive to operate at max frequency.
The level of detection and the target value do not
correspond with each other.
• PID control keeps the difference between target and detection values at 0. Set the input level
for the values relative to one another.
• Use analog input gains H3-03/11 to adjust PID target and feedback signal scaling.
Reverse drive output frequency and speed detection.
When output frequency rises, the sensor detects a
speed decrease.
Set PID output for reverse characteristics (b5-09 = “1”).
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Insufficient Motor Torque
Cause
Possible Solutions
Auto-Tuning has not yet been performed (required for
OLV Control).
Perform Auto-Tuning.
The control mode was changed after performing Auto-
Tuning.
Perform Auto-Tuning again.
Only Line-to-Line Resistance Auto-Tuning was
performed.
Perform Rotational Auto-Tuning.
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Motor Rotates After the Drive Output is Shut Off
Cause
Possible Solutions
Low DC Injection Braking and the drive cannot
decelerate properly.
• Adjust the DC Injection braking settings.
• Increase the value of b2-02 (DC Injection Braking Current).
• Increase the b2-04 (DC Injection Braking Time at Stop).
6.9 Troubleshooting without Fault Display
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YASKAWA ELECTRIC SIEP C710606 18F YASKAWA AC Drive – V1000 Technical Manual