Drive Frequency Reference Differs From The Controller Frequency Reference; Command; Unstable Motor Speed When Using Pm Motor - YASKAWA GA700 Technical Manual

Cause
Motor characteristics and drive parameter settings are
incompatible with one another.
Although the drive is operating in vector control mode,
Auto-Tuning has not been performed.
The Stall Prevention level during acceleration set too low.
The Stall Prevention level during run has been set too low.
Drive reached the limitations of the V/f motor control
method.
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Drive Frequency Reference Differs from the Controller Frequency Reference

Command

Cause
The analog input gain and bias for the frequency reference
input are set to incorrect values.
Frequency bias signals are being entered via analog input
terminals A1 to A3 and the sum of all signals builds the
frequency reference.
During low speed operation the motor rotates faster than
the frequency reference.
PID control is enabled.
◆

Unstable Motor Speed When Using PM Motor

Cause
E5-01 [PM Motor Code Selection] is not set correctly.
Drive is attempting to operate the motor beyond the speed
control range listed in the specifications.
The motor is operating at a speed reference of 5% or lower. Use a different drive to operate a motor at a speed reference of 5% or lower.
YASKAWA ELECTRIC SIEP C710617 01B YASKAWA AC Drive GA700 Technical Manual
6.10 Troubleshooting without Fault Display
Possible Solution
• Set the correct V/f pattern so that it matches the characteristics of the
motor being used.
• Check the V/f pattern set to E1-03 [V/f Pattern Selection].
• Perform Rotational Auto-Tuning.
• Perform Auto-Tuning.
• Calculate motor data and reset motor parameters.
• Switch to A1-02 = 0 [Control Method Selection = V/f Control].
Increase the value set in L3-02 [Stall Prevent Level during Accel].
Note:
If L3-02 is set too low, acceleration may be taking too long.
Increase the value set in L3-06 [Stall Prevent Level during Run].
Note:
If L3-06 is set too low, speed will drop as the drive outputs torque.
• The motor cable may be long enough (over 50 m) to require Auto-Tuning
for line-to-line resistance.
• Change the V/f pattern to "High Starting Torque."
• Consider switching to Vector Control mode.
Note:
Be aware that V/f Control is comparatively limited when it comes to
producing torque at low speeds.
Possible Solution
Check the gain and bias settings for the analog inputs that are used to set
the frequency reference.
• Terminal A1: H3-03 [Terminal A1 Gain Setting], H3-04 [Terminal A1
Bias Setting]
• Terminal A2: H3-11 [Terminal A2 Gain Setting], H3-12 [Terminal A2
Bias Setting]
• Terminal A3: H3-07 [Terminal A3 Gain Setting], H3-08 [Terminal A3
Bias Setting]
• Check whether two or more of H3-02, H3-10, H3-06 [MFAI Function
Select] have a setting value of 0, and change the settings if necessary.
• Check if the analog input values assigned to terminals A1, A2, and A3
are appropriate using U1-13 to U1-15 [Terminal A1, A2, A3 Input
Voltage].
Lower the value set in n4-70 [SpdCommandCompensator ofLow-Freq].
If PID control is not necessary, set b5-01 = 0 [PID Function Setting =
Disabled].
Note:
When PID control is enabled, the drive adjusts the output frequency
according to the target value. The drive will only accelerate to the
maximum output frequency set in E1-04 [Maximum Output Frequency]
while PID control is active.
Possible Solution
See "Motor Performance Fine-Tuning" in the technical manual.
Check the speed control range and adjust the speed accordingly.
Contact Yaskawa or your nearest sales representative.
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