590
6. PROTECTIVE FUNCTIONS
6.5 Check first when you have a trouble
6.5.7 Acceleration/deceleration is not smooth
6.5.8 Speed varies during operation
Under Advanced magnetic flux vector control, the output frequency varies between 0 and 2 Hz as the load fluctuates. This is
a normal operation and not a fault.
Check
points
Possible cause Countermeasure Refer to
page
Parameter
setting
Acceleration/deceleration time is too short. Increase the acceleration/deceleration time. 190
Torque boost (Pr.0, Pr.46) setting is improper
under V/F control, so the stall prevention
function is activated.
Increase/decrease the Pr.0 Torque boost setting value by
0.5% increments so that stall prevention does not occur.
538
The base frequency does not match the motor
characteristics.
Under V/F control, set Pr.3 Base frequency, Pr.47 Second V/
F (base frequency).
539
Under Advanced magnetic flux vector control or PM motor
control, set Pr.84 Rated motor frequency.
145
Regeneration avoidance operation is
performed
If the frequency becomes unstable during regeneration
avoidance operation, decrease the setting of Pr.886
Regeneration avoidance voltage gain.
559
Load Stall prevention (torque limit) function is
activated due to a heavy load.
Reduce the load weight. ―
Parameter
setting
Set Pr.22 Stall prevention operation level higher according to
the load. (If Pr.22 is set too high, an overcurrent trip (E.OC[]) is
likely to occur.)
257
Motor Check the capacities of the inverter and the motor. ―
Check
points
Possible cause Countermeasure Refer to
page
Load Load varies during an operation. Select Advanced magnetic flux vector control. 145
Input signal Frequency setting signal is varying. Check the frequency setting signal. ―
The frequency setting signal is affected by
EMI.
Set filter to the analog input terminal using Pr.74 Input filter
time constant, Pr.822 Speed setting filter 1.
326
Take countermeasures against EMI, such as using shielded
wires for input signal lines.
73
Malfunction is occurring due to the undesirable
current generated when the transistor output
unit is connected.
Use terminal PC (terminal SD when source logic) as a common
terminal to prevent a malfunction caused by undesirable
current.
55
Multi-speed command signal is chattering. Take countermeasures to suppress chattering. ―
Parameter
setting
Fluctuation of power supply voltage is too
large.
Under V/F control, change the Pr.19 Base frequency voltage
setting (approximately by 3%).
539
Pr.80 Motor capacity and Pr.81 Number of
motor poles are not appropriate for the motor
capacity under Advanced magnetic flux vector
control, or PM motor control.
Check the settings of Pr.80 and Pr.81. 145
Wiring length exceeds 30 m when Advanced
magnetic flux vector control, or PM motor
control is selected.
Perform offline auto tuning. 353
Under V/F control, wiring is too long and a
voltage drop occurs.
In the low-speed range, set 0.5% in Pr.0 Torque boost. 538
Change the control method to Advanced magnetic flux vector
control.
145
Hunting occurs by the generated vibration, for
example, when structural rigidity at load side is
insufficient.
Disable automatic control functions, such as the energy saving
operation, fast-response current limit operation, regeneration
avoidance function, Advanced magnetic flux vector control, stall
prevention, and online auto tuning.
Under PID control, set smaller values to Pr.129 PID
proportional band and Pr.130 PID integral time.
Adjust so that the control gain decreases and the level of safety
increases.
―
Change Pr.72 PWM frequency selection setting. 179
To Next Page
Loading...
Need help?
General
