Cause
Possible Solutions
Load is too heavy.
• Reduce the load so that the output current remains within the motor-rated current.
• In extruder and mixer applications, the load will sometimes increase as the temperature drops.
Check if the mechanical brake is fully releasing as it should.
Acceleration time has been set too
long.
Check if the acceleration time parameters have been set too long (C1-01, -03).
Motor characteristics and drive
parameter settings are
incompatible with one another in
V/f Control.
• Set the correct V/f pattern so that it matches the characteristics of the motor being used.
• Check the motor data and adjust V/f pattern settings.
Incorrect frequency reference
setting.
• Check the multi-function analog input settings.
• Ensure the analog input value is set to the right value (U1-13).
The Stall Prevention level during
acceleration and deceleration set
too low.
• Check the Stall Prevention level during acceleration (L3-02).
• If L3-02 is set too low, acceleration will take a fair amount of time.
• Increase L3-02.
The Stall Prevention level during
run has been set too low.
• Check the Stall Prevention level during run (L3-06).
• If L3-06 is set too low, speed will drop as the drive outputs torque.
• Increase the setting value.
n
Drive Frequency Reference Differs from the Controller Frequency Reference Command
Cause
Possible Solutions
The analog input frequency gain and bias are set to
incorrect values.
• Check the frequency reference terminal input gain level assigned to terminal A1 (parameter
H3-03).
n
Poor Speed Control Accuracy
Cause
Possible Solutions
Slip compensation function disabled or set up
incorrectly.
• Adjust the slip compensation gain (C3-01).
n
Deceleration Takes Longer Than Expected when Using a Braking Resistor
Cause
Possible Solutions
L3-04 is set incorrectly.
• Check the Stall Prevention Level during deceleration (L3-04).
• If a braking resistor option has been installed, disable Stall Prevention during deceleration
(L3-04 = “0”).
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 is
insufficient 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
by the drive rated current.
Switch to a larger capacity drive.
n
Motor Hunting Occurs When Operating With a Light Load
Cause
Possible Solutions
Carrier frequency is too high.
Lower the carrier frequency setting C6-02.
Large V/f setting value at low speeds triggers
overexcitation.
• Use parameters E1-04 through E1-10 to set the V/f pattern in relation to the load
characteristics.
The maximum output frequency and the base
frequency reference are not set properly in
relationship to each other.
Set the proper values for the maximum output frequency and base frequency (E1-04, E1-06).
Hunting Prevention is set up incorrectly.
Adjust the hunting prevention gain (n1-02).
n
Noise From Drive or Output Lines When the Drive is Powered On
Cause
Possible Solutions
Relay 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.
n
Ground Fault Circuit Interrupter (GFCI) Trips During Run
Cause
Possible Solutions
Excessive leakage current trips
MCCB.
• 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.
• Install a noise filter or reactor on the output side of the drive.
6.8 Troubleshooting without Fault Display
136
SIEP C710606 33A OYMC AC Drive – J1000 User Manual
