• If this setting is too high, excessive speed or torque ripple can result.
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L3-21: Accel/Decel Rate Calculation Gain
Determines the proportional gain used by overvoltage suppression (L3-11 = 1), Single Drive KEB 2 (L2-29 = 1), and
Intelligent Stall Prevention during deceleration (L3-04 = 2) in order to calculate acceleration and deceleration rates.
Adjustment for Single Drive KEB 2 (L2-29 = 1) and Intelligent Stall Prevention During Deceleration
• Reduce L3-21 in steps of 0.05 if there is a fairly large speed or current ripple.
• Small reductions of L3-21can also help solve problems with overvoltage and overcurrent.
• Decreasing this setting too much can result in a slow DC bus voltage control response and may also lengthen
deceleration times beyond optimal levels.
Adjustment for Overvoltage Suppression
• Increase this setting in steps of 0.1 if overvoltage occurs as a result of a regenerative load when overvoltage
suppression is enabled (L3-11 = 1).
• If there is a fairly large speed ripple when overvoltage suppression is enabled, then decrease L3-21 in steps of 0.05.
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L3-24: Motor Acceleration Time for Inertia Calculations
Sets the time it takes to accelerate the motor from stop to the maximum speed at motor rated torque. This parameter
should be set when using Single Drive KEB 2 (L2-29 = 1), Intelligent Stall Prevention during deceleration (L2-04 = 2),
or the overvoltage suppression function (L3-11 = 1).
Automatic Parameter Setup
In Closed Loop Vector Control for induction motors or PM motors, the Inertia Auto-Tuning function can be used to let
the drive automatically adjust this parameter. Refer to Auto-Tuning on page 109.
Manual Parameter Setup
Calculations are made as follows:
The rated torque can be calculated as follows:
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L3-25: Load Inertia Ratio
Determines the ratio between the rotor inertia and the load. Set this parameter when using Single Drive KEB 2 (L2-29 =
1), Intelligent Stall Prevention during deceleration (L3-04 = 2), or the overvoltage suppression function (L3-11 = 1).
When set incorrectly, a fairly large current ripple can result during Single Drive KEB 2 (L2-29 = 1) and overvoltage
suppression (L3-11 = 1) or other faults such as ov, Uv1, and oC may occur.
No.
<1> This value is reset to its default value when the control mode is changed (A1-02). The value shown here is for Open Loop Vector Control.
Name Setting Range Default
L3-21 Accel/Decel Rate Calculation Gain 0.10 to 10.00 <1>
No.
<1> Parameter L3-24 is defaulted for a Yaskawa standard 4-pole motor. During Auto-Tuning, L3-24 will be initialized to a Yaskawa standard 4-pole
motor if parameter E2-11 is changed. This value also changes based on the motor code set to E5-01 when using the Open Loop Vector Control
Mode for PM motors.
Name Setting Range Default
L3-24 Motor Acceleration Time for Inertia Calculations 0.001 to 10.000 s
Determined by o2-04, C6-01, E2-11, and E5-01
<1>
No. Name Setting Range Default
L3-25 Load Inertia Ratio 1.0 to 1000.0 1.0
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