Problem Parameter No. Corrective Action Default SuggestedSettingOscillation at start or themotor stallsPull-In Current duringAccel/Decel (n8-51) Increase the pull-in current in n8-51 50% Increase in stepsof 5%DC Injection BrakingCurrent (b2-02), DCInjection Time at Start(b2-03)Use DC Injection Braking at start to align the rotor. This maycause a short reverse rotation at start. b2-02 = 50%b2-03 = 0.00 sb2-03 = 0.5 sIncrease b2-02 ifneededLoad Inertia Ratio(n8-55)Increase the load inertia ratio.Note: Setting this value too high can causeovercompensation and motor oscillation.0 Close to the actualload inertia ratioStalling or oscillationoccur when load isapplied during constantspeedPull-In CurrentCompensation TimeConstant (n8-47) Reduce n8-47 if hunting occurs during constant speed 5.0 s Reduce inincrementsof 0.2 sPull-In Current (n8-48) Increase the pull-in current in n8-48. 30% Increase inincrements of 5%Load Inertia Ratio(n8-55) Increase the load inertia ratio. 0 Close to the actualload inertia ratioHunting or oscillationoccur Speed feedbackDetection Gain (n8-45) Reduce the speed feedback detection gain in n8-45. 0.80 Increase inincrements 0.05STo fault trips when theload is not excessivelyhighInduced VoltageConstant(E5-09 or E5-24)• Check and adjust the induced voltage constant.• Check the motor nameplate and the data sheet or contact themotor manufacturer.Depends ondrivecapacityRefer to the motordata sheet or thenameplate.Stalling or STo occurs athigh speed as the outputvoltage becomessaturatedOutput Voltage Limit(n8-62) Set the value of the input voltage to parameter n8-62 600 Vac(600 V class) Set equal to inputvoltageu Parameters to Minimize Motor Hunting and OscillationIn addition to the parameters discussed on pages 194 and 194, parameters in Table 5.3 indirectly affect motor hunting andoscillation.Table 5.3 Parameters that Affect Control Performance in ApplicationsName(Parameter No.) ApplicationAccel/Decel Time(C1-01 through C1-11) Adjusting accel and decel times will affect the torque presented to the motor during acceleration or deceleration.S-Curve Characteristics(C2-01 and C2-02) Prevents shock at the beginning and end of acceleration and deceleration.Jump Frequency(d3-01 through d3-04) Skips over the resonant frequencies of connected machinery.Analog Filter Time Constant(H3-13) Prevents fluctuation in the analog input signal due to noise.Stall Prevention(L3-01 through L3-06, L3-11)• Prevents motor speed loss and overvoltage when the load is too heavy or during sudden acceleration/deceleration.• Adjustment is not normally necessary because Stall Prevention is enabled as a default.5.2 Motor Performance Fine-TuningYASKAWA TOEP YAIZ1U 03B YASKAWA AC Drive – Z1000 User Manual 1955 Troubleshooting
