u Drive Frequency Reference Differs from the Controller Frequency Reference CommandCause Possible SolutionsThe analog input gain and bias for the frequencyreference input are set to incorrect values.• 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 and check parameters H3-11 and H3-12 forinput A2.• Set these parameters to the appropriate values.A frequency bias signal is being entered via analoginput terminals A1 to A2.• If multi-function analog inputs A1 and A2 are set for frequency reference bias (H3-02 or H3-10is set to 0), then the sum of all signals builds the frequency reference.• Make sure that H3-02 and H3-10 are set appropriately.• Check the input level set for terminals A1 and A2 (U1-13 and U1-14).PI control is enabled, and the drive is consequentlyadjusting the output frequency to match the PI setpoint.The drive will only accelerate to the maximum outputfrequency set in E1-04 while PI control is active.If PI control is not necessary for the application, disable it by setting b5-01 to 0.u Excessive Motor Oscillation and Erratic RotationCause Possible SolutionsPoor balance between motor phases. Check drive input power voltage to ensure that it provides stable power.Hunting prevention function is disabled. Set n1-01 to 1 to enable Hunting Prevention.u Deceleration Takes Longer than ExpectedCause Possible SolutionsL3-04 is set incorrectly. Check the Stall Prevention level during deceleration (L3-04).The deceleration time is set too long. Set deceleration to more appropriate time (C1-02 and C1-04).Insufficient motor torque.• Assuming parameter settings are normal and that no overvoltage occurs when there isinsufficient torque, it is likely that the demand on the motor has exceeded the motor capacity.• Use a larger motor.Load exceeded the internal torque limit determined bythe drive rated current. Switch to a larger capacity drive.u Noise From Drive or Motor Cables When the Drive is Powered OnCause Possible SolutionsRelay switching in the drive generates excessive noise.• Lower the carrier frequency (C6-02).• Install a noise filter on the input side of drive input power.• Install a noise filter on the output side of the drive.• Place the wiring inside a metal conduit to shield it from switching noise.• Ground the drive and motor properly.• Separate the main circuit wiring and the control lines.• Make sure wires and the motor have been properly grounded.u Ground Fault Circuit Interrupter (GFCI) Trips During RunCause Possible SolutionsExcessive leakage current trips GFCI.• Check the wiring and rating of peripheral devices.• Increase the GFCI sensitivity or use GFCI with a higher threshold.• Lower the carrier frequency (C6-02).• Reduce the length of the cable used between the drive and the motor.• Disable the internal EMC filter.5.10 Troubleshooting without Fault DisplayYASKAWA TOEP YAIZ1U 03B YASKAWA AC Drive – Z1000 User Manual 2395 Troubleshooting
