YASKAWA V1000 Technical Manual page 284

6.9 Troubleshooting without Fault Display
n Poor Speed Control Accuracy
Cause
Drive reached the slip compensation limit.
Motor-rated voltage is set too high in Open Loop
Vector Control.
Auto-Tuning did not complete properly for Open
Loop Vector Control.
n Deceleration Takes Longer Than Expected with Dynamic Braking Enabled
Cause
L3-04 is set incorrectly.
The deceleration time is set too long.
Insufficient motor torque.
Reaching the torque limit.
Load exceeded the internal torque limit determined
by the drive rated current.
n Motor Hunting Occurs When Operating With a Light Load
Cause
Carrier frequency is too high.
Large V/f setting value at low speeds triggers
overexcitation.
The maximum output frequency and the base
frequency reference are not set properly in
relationship to each other.
Hunting Prevention is disabled (V/f control only).
n Load Falls When Brake is Applied (Hoist-Type Applications)
Cause
The timing for the brake to close and release is not
set properly.
Insufficient DC Injection Braking.
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• Check the slip compensation limit (C3-03).
• Increase the value set to C3-03.
• The input voltage for the drive determines the maximum output voltage. A drive with an
input of 200 Vac can only output a maximum of 200 Vac. Open Loop Vector Control
sometimes calculates an output voltage reference value that exceeds the maximum drive
output voltage level, resulting in a loss of speed control accuracy.
• Use a motor with a lower voltage rating (a vector control motor).
• Increase the input power voltage.
• Perform Auto-Tuning again.
• Check the Stall Prevention Level during deceleration (L3-04).
• If a braking resistor option has been installed, disable Stall Prevention during deceleration
(L3-04 = "0").
Set deceleration to more appropriate time (C1-02, C1-04, C1-06, C1-08).
• Assuming parameter settings are normal and that no overvoltage occurs when there is
insufficient torque, it is likely that the demand on the motor has exceeded the motor capacity.
• Use a larger motor.
• Check the settings for the torque limit (L7-01 through L7-04).
• If the torque limit is enabled, deceleration might take longer than expected because the drive
cannot output more torque than the limit setting. Ensure the torque limit is set to a large
enough value.
• Increase the torque limit setting.
• If multi-function analog input terminal A1 or A2 is set to torque limit (H3-02 or H3-10
equals 10, 11, 12, or 15), ensure that the analog input levels are set to the correct levels.
• Ensure H3-02 and H3-10 are set to the right levels.
• Ensure the analog input is set to the correct value.
Switch to a larger capacity drive.
Lower the carrier frequency setting C6-02.
• 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.
Set the proper values for the maximum output frequency and base frequency (E1-04, E1-06).
• Enable Hunting Prevention by setting n1-01 = "1".
• (OLV only) Increase the speed feedback detection control gain and time constant (n2-01,
n2-02).
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.
Increase the amount of DC Injection Braking (b2-02).
YASKAWA ELECTRIC SIEP C710606 16C YASKAWA AC Drive – V1000 Technical Manual
Possible Solutions
Possible Solutions
Possible Solutions
Possible Solutions