YASKAWA CIMR-VU BA0001 Technical Manual page 308

6.9 Troubleshooting without Fault Display
Cause
The frequency reference is too low.
n Motor Stops During Acceleration or When a Load is Connected
Cause
• The load is too heavy.
• The limit of motor response may be reached during
rapid acceleration. This may be a result of improper
stall prevention or automatic torque boost function
adjustment.
n Motor Rotates in One Direction Only
Cause
"Reverse run prohibited" is selected. If b1-04 (Reverse
Prohibit Operation) is set to 1 (reverse run prohibited),
the drive will not accept a reverse run command.
The drive prohibits reverse rotation.
A Reverse run signal has not been entered, although 3-
Wire sequence is selected.
n
Motor Operates at a Higher Speed than the Speed Command
Cause
PID is enabled. If the PID mode is enabled (b5-01 = 1
to 4), the drive output frequency will change to regulate
the process variable to the target setpoint. The PID can
command a speed up to maximum output frequency
(E1-04).
n
Poor Speed Control Accuracy Above Base Speed in Open Loop Vector Motor Control Method
Cause
The maximum output voltage of the drive is
determined by its input voltage. Vector control uses
voltage to control the currents within the motor. If the
vector control voltage reference value exceeds the
drive output voltage capability, the speed control
accuracy will decrease because the motor currents
cannot be properly controlled.
n Peripheral Devices Affected by Drive Operation
Cause
Radio frequency interference may be generated by
drive output PWM waveform.
n Ground Fault Interrupter Activates When Drive is Running
Cause
The output of the drive is a series of high frequency
pulses (PWM), so there is a certain amount of leakage
current. This may cause the ground fault interrupter to
operate and cut off the drive input power.
308
• If the frequency reference is set below the frequency set in E1-09 (Minimum Output
Frequency), the drive will not operate.
• Raise the frequency reference to at least the minimum output frequency.
Increase the acceleration time (C1-01) or reduce the motor load. Also, consider increasing the
motor size and/or drive size.
Set b1-04 = "0" to allow reverse run operation.
• Check parameter b1-04.
• Set the drive to allow the motor to rotate in reverse (b1-04 = "0").
• Make sure that one of the input terminals S3 to S5 used for the 3-Wire sequence has been set
for reverse.
If PID operation is not target, disable PID by setting b5-01 = "0".
Use a motor with a lower rated voltage compared to the input voltage.
• Change the Carrier Frequency Selection (C6-02) to lower the carrier frequency. This will help
to reduce the amount of transistor switching noise.
• Install an Input Noise Filter at the input power terminals.
• Install an Output Noise Filter at the motor terminals.
• Use conduit. Metal can shield electrical noise.
• Ground the drive and motor.
• Separate main circuit wiring from control wiring.
• Change to a ground fault interrupter with a higher leakage current detection level (such as, a
sensitivity current of 200 mA or greater per Unit, with an operating time of 0.1 s or more), or
one that incorporates high-frequency corrective actions.
• Change the Carrier Frequency Selection (C6-02) to lower the carrier frequency.
Note: Leakage current increases in proportion to cable length.
YASKAWA ELECTRIC SIEP C710606 18F YASKAWA AC Drive – V1000 Technical Manual
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