Yaskawa AC Drive-P1000 Industrial Fan - Manual (Page 332)

Cause Possible Solutions
Drive reached the limitations of the V/f motor control
method.
• The motor cable may be long enough (over 50 m) to require Auto-Tuning for line-to-line
resistance.
• Be aware that V/f Control is comparatively limited when it comes to producing torque at low
speeds.
u Drive Frequency Reference Differs from the Controller Frequency Reference Command
Cause Possible Solutions
The analog input gain and bias for the frequency
reference input are set to incorrect values.
• Check the gain and bias settings for the analog inputs that are used to set the frequency reference.
Check parameters H3-03 and H3-04 for input A1, check parameters H3-11, and H3-12 for input
A2, and check parameters H3-07 and H3-08 for input A3.
• Set these parameters to the appropriate values.
A frequency bias signal is being entered via analog
input terminals A1 to A3.
• If more than one of multi-function analog inputs A1 to A3 is set for frequency reference bias
(H3-02, H3-10, or H3-06 is set to “0”), then the sum of all signals builds the frequency reference.
• Make sure that H3-02, H3-10, and H3-06 are set appropriately.
• Check the input level set for terminals A1 to A3 (U1-13 to U1-15).
PID control is enabled, and the drive is consequently
adjusting the output frequency to match the PID
setpoint. The drive will only accelerate to the
maximum output frequency set in E1-04 while PID
control is active.
If PID control is not necessary for the application, disable it by setting b5-01 to 0.
u Excessive Motor Oscillation and Erratic Rotation
Cause Possible Solutions
Poor balance between motor phases. Check drive input power voltage to ensure that it provides stable power.
Hunting prevention function is disabled.
• Enable Hunting Prevention (n1-01 = 1).
• Increase the AFR gain (n2-01) or the AFR time constant (n2-02).
u Deceleration Takes Longer Than Expected with Dynamic Braking Enabled
Cause Possible Solutions
L3-04 is set incorrectly.
• Check the Stall Prevention level during deceleration (L3-04).
• If a dynamic braking option has been installed, disable Stall Prevention during deceleration
(L3-04 = 0).
The deceleration time is set too long. Set deceleration to more appropriate time (C1-02, C1-04).
Insufficient motor torque.
• 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.
Reaching the torque limit.
• 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 high enough
value.
• Increase the torque limit setting.
• If multi-function analog input terminal A1, A2, or A3 is set to torque limit (H3-02, H3-10, or
H3-06 equals 10, 11, 12, or 15), ensure that the analog input levels are set to the correct levels.
• Ensure H3-02, H3-10, and H3-06 are set to the right levels.
• Ensure the analog input is set to the correct value (U1-13 to U1-15).
Load exceeded the internal torque limit determined by
the drive rated current.
Switch to a larger capacity drive.
6.10 Troubleshooting without Fault Display
332 YASKAWA SIEP YAIP1U 01B AC Drive - P1000 Technical Manual