Yaskawa F7 Drive User Manual User Manual
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Diagnostics & Troubleshooting 6 - 22
If The Direction of the Motor Rotation is Reversed
If the motor rotates in the wrong direction, the motor output wiring may be incorrect. When the Drive operates in the forward
direction, the forward direction of the motor will depend on the manufacturer and the motor type, so be sure to check the motor
specification.
The direction of motor rotation can be reversed by switching any two wires among U/TI, V/T2, and W/T3. If using an encoder,
the polarity will also have to be switched.
If the Motor Stalls or Acceleration is Slow
The following causes are possible:
The stall prevention level during acceleration is too low.
If the value set for L3-02 (Stall Prevention Acceleration Level) is set too low, the acceleration time will be increased. Check that
the set value is suitable and that the load is not too large for the motor.
The stall prevention level during running is too low.
If the value set for L3-06 (Stall Prevention Level during Running) is too low, the motor speed and torque will be limited. Check
that the values set are suitable.
If the Motor Operates at a Higher Speed Than the Speed Command
The following causes are possible:
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 desired
setpoint. The PID can command a speed up to maximum output frequency (E1-04).
If There is Low Speed Control Accuracy Above Base Speed in Open-loop
Vector Control Method
The Drive’s maximum output voltage is determined by its input voltage (For example, if 230Vac is input, then the maximum out-
put voltage will be 230Vac). 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. Use a motor with a low rated voltage compared to the input voltage, or change to flux vector con-
trol.