Motor Stalls During Acceleration Or Acceleration Time Is Too Long - YASKAWA U1000 Series Technical Manual

 Motor Stalls during Acceleration or Acceleration Time is Too Long
Cause
Torque limit has been reached or current suppression keeps the drive
from accelerating.
Load is too heavy.
Torque limit is not set properly.
Frequency reference is too low.
Load is too heavy.
Acceleration time has been set too long.
Motor characteristics and drive parameter settings are incompatible
with one another.
Although the drive is operating in Open Loop Vector motor control
method, Auto-Tuning has not been performed.
Incorrect frequency reference setting.
The Stall Prevention level during acceleration and deceleration 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.
 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.
A frequency bias signal is being entered via analog input terminals
A1 to A3.
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.
 Excessive Motor Oscillation and Erratic Rotation
Cause
Poor balance between motor phases.
Hunting prevention function is disabled.
 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.
YASKAWA ELECTRIC SIEP C710636 03A YASKAWA U1000 Technical Manual
6.10 Troubleshooting without Fault Display
Take the following steps to resolve the problem:
• Reduce the load.
• Increase motor capacity.
Note: Although the drive has a Stall Prevention function and a Torque Compensation Limit function, accelerating too
quickly or trying to drive an excessively large load can exceed the capabilities of the motor.
Check the torque limit setting.
• Check the maximum output frequency (E1-04).
• Increase E1-04 if it is set too low.
Check U1-01 for proper frequency reference.
Check if a frequency reference signal switch has been set to one of the multi-function input terminals.
Check for low gain level set to terminals A1, A2, or A3 (H3-03, H3-11, H3-07).
• Reduce the load so that the output current remains within the motor rated current.
• In extruder and mixer applications, the load will sometimes increase as the temperature drops.
• Increase the acceleration time.
• Check if the mechanical brake is fully releasing as it should.
Check if the acceleration time parameters have been set too long (C1-01, C1-03, C1-05, C1-07).
• 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.
• Execute Rotational Auto-Tuning.
• Perform Auto-Tuning.
• Calculate motor data and reset motor parameters.
• Switch to V/f Control (A1-02 = 0).
• Check the multi-function analog input settings. Multi-function analog input terminal A1, A2, or A3 is set for
frequency gain (H3-02, H3-10, or H3-06 is set to "1"), but there is no voltage or current input provided.
• Make sure H3-02, H3-10, and H3-06 are set to the proper values.
• See if the analog input value is set to the right value (U1-13 to U1-15).
• Check the Stall Prevention level during acceleration (L3-02).
• If L3-02 is set too low, acceleration may be taking too long.
• Increase L3-02.
• Check the Stall Prevention level during run (L3-06).
• If L3-06 is set too low, speed will drop as the drive outputs torque.
• Increase the setting value.
• 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.
• Consider switching to Open Loop Vector Control.
• 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.
• 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).
If PID control is not necessary for the application, disable it by setting b5-01 to "0".
Check drive input power voltage to ensure that it provides stable power.
• Enable Hunting Prevention (n1-01 = 1).
• Increase the AFR gain (n2-01) or the AFR time constant 1 (n2-02).
Refer to Notes on Controlling the Brake when Using the Hoist Application Preset on page 113.
Increase the amount of DC Injection Braking Current (b2-02).
Possible Solutions
Possible Solutions
Possible Solutions
Possible Solutions
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