Yaskawa Z1000U HVAC Matrix Bypass - Manual (Page 194)

5.9 n: Special Adjustments
These parameters control a variety of specialized adjustments and functions, including Hunting Prevention and High Slip
Braking.
u n1: Hunting Prevention
Hunting Prevention prevents 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.
n n1-01: Hunting Prevention Selection
Enables and disables the Hunting Prevention function.
Note: Disable Hunting Prevention when drive response is more important than suppressing motor oscillation. This function may be disabled
without problems in applications with high inertia loads or relatively heavy loads.
No. Name Setting Range Default
n1-01 Hunting Prevention Selection 0, 1 1
Setting 0: Disabled
Setting 1: Enabled
n n1-02: Hunting Prevention Gain Setting
Sets the gain for the Hunting Prevention Function.
No. Name Setting Range Default
n1-02 Hunting Prevention Gain Setting 0.00 to 2.50 1.00
Although this parameter rarely needs to be changed, it may require adjustment in the following situations:
• 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.
u n3: Overexcitation Braking
n n3-13: Overexcitation Deceleration Gain
Multiplies a gain to the V/f pattern output value during Overexcitation Deceleration to determine the level of overexcitation.
The drive returns to the normal V/f value after the motor has stopped or when it is accelerating to the frequency reference.
No. Name Setting Range Default
n3-13 Overexcitation Deceleration Gain 1.00 to 2.00 1.10
The optimum setting for n3-13 depends on the motor flux saturation characteristics.
• Gradually increase the gain to improve the braking power of Overexcitation Deceleration.
• Lower n3-13 when flux saturation characteristics cause overcurrent. A high setting sometimes causes overcurrent (oC),
motor overload (oL1), or drive overload (oL2).
5.9 n: Special Adjustments
194 YASKAWA SIEP YAIZ1D 01A Z1000U HVAC MATRIX Drive Bypass Technical Manual