N: Special Adjustments - YASKAWA U1000 Series Technical Manual

5.9

n: Special Adjustments

These parameters handle a variety of specialized adjustments and functions, including Hunting Prevention, AFR Control,
resistance between motor lines, and PM motor control functions.
 n1: Hunting Prevention
Hunting Prevention keeps the drive from hunting as a result of low inertia and operating with light load. Hunting often
occurs with a high carrier frequency and an output frequency below 30 Hz.
n1-01: Hunting Prevention Selection

Enables or disables the Hunting Prevention function.
Note: This function is available only when using V/f Control. Hunting Prevention should be disabled when drive response is more
important than suppressing motor oscillation. This function can also be disabled without any problems in applications with high
inertia loads or relatively heavy loads.
No.
n1-01
Setting 0: Disabled
Setting 1: Enabled
n1-02: Hunting Prevention Gain Setting

Sets the gain for the Hunting Prevention Function.
No.
n1-02
Normally, n1-02 does not need to be changed, but adjustment may help under the following conditions:
• If the motor vibrates while lightly loaded and n1-01 = 1, increase the gain by 0.1 until vibration ceases.
• If the motor stalls while n1-01 = 1, decrease the gain by 0.1 until the stalling ceases.
n1-03: Hunting Prevention Time Constant

Determines how responsive the Hunting Prevention function is (affects the primary delay time for Hunting Prevention).
No.
n1-03
Normally, n1-03 does not need to be changed, but adjustment may help under the following conditions:
• Increase this value for applications with a large load inertia. A higher setting leads to slower response, though, which
can result in oscillation at lower frequencies.
• Lower this setting if oscillation occurs at low speed.
n1-05: Hunting Prevention Gain while in Reverse

This parameter is the same as n1-02, except that it is used when rotating in reverse.
Gain Setting on page 281.
Note: When set to 0 ms, n1-02 is enabled even when the drive is operating in reverse.
No.
n1-05
 n2: Speed Feedback Detection Control (AFR) Tuning
These parameters are used to achieve speed stability when a load is suddenly applied or removed.
Note: Before making changes to the AFR parameters, make sure all motor parameters are set properly or perform Auto-Tuning.
YASKAWA ELECTRIC SIEP C710636 03A YASKAWA U1000 Technical Manual
Name
Hunting Prevention Selection
Name
Hunting Prevention Gain Setting
Name
Hunting Prevention Time Constant
Name
Hunting Prevention Gain while in Reverse
5.9 n: Special Adjustments
Setting Range Default
0 or 1
Setting Range Default
0.00 to 2.50
Setting Range Default
0 to 500 ms Determined by o2-04
Refer to n1-02: Hunting Prevention
Setting Range Default
0.00 to 2.50
1
1.00
5
0.00
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