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Motor Hunting Occurs When Operating With a Light Load
Cause
Possible Solutions
Carrier frequency is too high.
Lower the carrier frequency setting C6-02.
Large V/f setting value at low speeds triggers
overexcitation.
• Select the proper V/f pattern (E1-03).
• Use parameters E1-04 through E1-10 to set the V/f pattern in relation to the load characteristics.
The maximum output frequency and the base
frequency reference are not set properly in relationship
to each other.
Set the proper values for the maximum output frequency and base frequency (E1-04, E1-06).
Hunting Prevention is disabled (V/f control only).
• Enable Hunting Prevention by setting n1-01 = “1”.
• (OLV only) Increase the speed feedback detection control gain and time constant (n2-01,
n2-02).
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Load Falls When Brake is Applied (Elevator-Type Applications)
Cause
Possible Solutions
The timing for the brake to close and release is not set
properly.
Use frequency reference detection for closing and releasing the brake.
• At start: Release the brake after creating enough torque.
• At stop: Close the brake when the motor still produces torque.
Make the following setting changes to hold the brake:
• Set the frequency detection inactive during baseblock (L4-07 = 0).
• Multi-function contact output terminal will switch on when the output frequency is greater than
the frequency detection level set in L4-01. Set L4-01 between 1.0 and 3.0 Hz.
• Slipping may occur when stopping because hysteresis is used in Frequency Reference 2 (where
the frequency agree setting in L4-02 is 2.0 Hz). To prevent this, change the setting to 0.1 Hz.
• Do not use the multi-function contact output setting “During Run” (H2-01 = 0) for the brake
signal.
Insufficient DC Injection Braking.
Increase the amount of DC Injection Braking (b2-02).
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Noise From Drive or Output Lines When the Drive is Powered On
Cause
Possible Solutions
Relay switching in the drive generates excessive
noise.
• Lower the carrier frequency (C6-02).
• Install a noise filter on the input side of drive input power.
• Install a noise filter on the output side of the drive.
• Place the wiring inside a metal conduit to shield it from switching noise.
• Ground the drive and motor properly.
• Separate the main circuit wiring and the control lines.
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Ground Fault Circuit Interrupter (GFCI) Trips During Run
Cause
Possible Solutions
Excessive leakage current trips MCCB.
• Increase the GFCI sensitivity or use GFCI with a higher threshold.
• Lower the carrier frequency (C6-02).
• Reduce the length of the cable used between the drive and the motor.
• Install a noise filter or reactor on the output side of the drive.
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Connected Machinery Vibrates When Motor Rotates
Excessive Motor Oscillation and Erratic Rotation
Cause
Possible Solution
Poor balance between motor phases.
Check drive input power voltage to ensure that it provides stable power.
Unexpected Noise from Connected Machinery
Cause
Possible Solutions
The carrier frequency is at the resonant frequency of
the connected machinery.
Adjust the carrier frequency using parameters C6-02 through C6-05.
The drive output frequency is the same as the resonant
frequency of the connected machinery.
• Adjust the parameters used for the Jump Frequency function (d3-01 through d3-04) to skip the
problem-causing bandwidth.
• Place the motor on a rubber pad to reduce vibration.
Note:
The drive may have trouble assessing the status of the load due to white noise generated when using Swing PWM (C6-02 = 7 to A).
6.9 Troubleshooting without Fault Display
YASKAWA ELECTRIC SIEP C710606 18F YASKAWA AC Drive – V1000 Technical Manual
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Troubleshooting