Command; The Motor Speed Is Not Stable When Using A Pm Motor; There Is Too Much Motor Oscillation And The Rotation Is Irregular - Omron Q2A Series Technical Manual

7.10 Troubleshooting Without Fault Display
Causes
The Stall Prevention level during run setting is too low.
Drive reached the limitations of the V/f motor control method.
◆
The Drive Frequency Reference Is Different than the Controller Frequency
Reference Command
Causes
The analog input gain and bias for the frequency reference input are set
incorrectly.
The drive is receiving frequency bias signals from analog input terminals
AI1 to AI3 and the sum of all signals makes the frequency reference.
Examine the gain and bias settings for the analog inputs that set the
frequency reference.
PID control is enabled.
◆

The Motor Speed Is Not Stable When Using a PM Motor

Causes
E5-01 [PM Mot Code Selection] is set incorrectly.
The drive is operating the motor at more than the specified speed control
range.
The motor is operating at a speed reference of 5% or lower.
The motor is hunting.
Hunting occurs at start.
Too much current is flowing through the drive.
Speed response is too slow.
◆

There Is Too Much Motor Oscillation and the Rotation Is Irregular

Causes
Unsatisfactory balance of motor phases.
The hunting prevention function is disabled.
298
Possible Solutions
Increase the value set in L3-06 [StallP Level@Run].
Note:
If the L3-06 value is too low, speed will decrease while the drive outputs torque.
• When the motor cable is longer than 50 m (164 ft.), do Auto-Tuning for line-to-line resistance.
• Set the V/f pattern to "High Starting Torque".
• Use a Vector Control method.
Note:
V/f control method does not provide high torque at low speeds.
Possible Solutions
Examine the gain and bias settings for the analog inputs that set the frequency reference.
• Terminal AI1: H3-03 [AI1 Gain Setting], H3-04 [AI1 Bias Setting]
• Terminal AI2: H3-11 [AI2 Gain Setting], H3-12 [AI2 Bias Setting]
• Terminal AI3: H3-07 [AI3 Gain Setting], H3-08 [AI3 Bias Setting]
• Examine parameters H3-02 [AI1 Function Selection], H3-10 [AI2 Function Selection], H3-06
[AI3 Function Selection]. If two or more of these parameters are set to 4 [FrqBIAS Frq],
change the settings.
• Use U1-13 [Terminal AI1 Input Lv], U1-14 [Terminal AI2 Input Lv], and U1-15 [Terminal
AI3 Input Lv ] to make sure that the analog input values set to terminals AI1, AI2, and AI3 are
applicable.
Reduce the value set in n4-70 [Speed Comp@LowFrequency].
If PID control is not necessary, set b5-01 = 0 [PID Enable = Disabled].
Note:
When PID control is enabled, the drive adjusts the output frequency as specified by the target
value. The drive will only accelerate to the maximum output frequency set in E1-04 [Max
Output Frequency] while PID control is active.
Possible Solutions
Refer to "Motor Performance Fine-Tuning" in the Technical Manual.
Examine the speed control range and adjust the speed.
Use a different drive to operate a motor at a speed reference of 5% or lower. Contact the
manufacturer.
Adjust these parameters to have the largest effect:
• n8-55 [Load Inertia]
• n8-45 [SpdFbck Det.Gain]
• C4-02 [Trq Comp Delay Time]
Increase the value set in C2-01 [Jerk@Start of Accel].
Set E5-01 [PM Mot Code Selection] correctly as specified by the motor. For special-purpose
motors, enter the correct value to E5-xx as specified by the motor test report.
Increases the setting value of n8-11 [Observ.Calc Gain2] in 10-unit increments.
Possible Solutions
• Make sure that the drive input power voltage supplies stable power.
• Set L8-05 = 0 [In PhaseLoss Selection = Disabled].
• Set n1-01 = 2 [HuntPrev Selection = Enabled (High Carrier)].
• Increase the value of n2-01 [AFR Gain] or n2-02 [AFR Time 1].
SIEPYEUOQ2A01A AC Drive Q2A Technical Manual