Stall Prevention Function
Chapter 6-3
6-3 Stall Prevention Function
A stall will occur if the motor cannot keep up with the rotating magnetic field on the motor stator side when a large load is applied to the motor or a sudden acceleration/deceleration is performed.
In the J7AZ, stall prevention functions can be set independently for accelerating, running, and decelerating conditions.
n55
Setting range
0, 1
Stall Prevention Level during Deceleration
Unit of setting
1
Changes during operation
Default setting 0
No
Set Values
0
1
Value Description
Stall prevention during deceleration
Stall prevention during deceleration
• If 1 is set, the motor will be decelerated according to the set deceleration time. If the deceleration time is too short, the main circuit may result in overvoltage.
• If 0 is set, the deceleration time will be automatically lengthened to prevent overvoltage.
Stall Prevention during Deceleration with n55 Set to 0
Output frequency
Deceleration time is controlled to prevent overvoltage.
Time
Deceleration time (Set value)
73
Stall Prevention Function
Chapter 6-3
n56
Setting range
Set Values
Stall Prevention Level during Acceleration
30 to 200 (%)
Changes during operation
Set Values 170
No
Unit of setting
1%
• This function is used to stop accelerating the load if the output current exceeds the set current value so that the Inverter will continue operating without stalling. The Inverter accelerates the load while the output current is the same as or less than the set value.
• Set the parameter as percentage based on the rated Inverter current as
100%.
• The default setting does not need any changes in normal operation.
• Decrease the set value if the capacity of the motor is smaller than that of the Inverter or the motor stalls with the default value.
The set value is normally 2 or 3 times higher than the rated current of the motor. Set this current as percentage based on the rated inverter current as 100%.
Stall Prevention during Acceleration
Output current n56 (stall prevention level during acceleration)
Output frequency
Time
The output frequency is controlled so that the Inverter will not stall.
Time
74
Stall Prevention Function
Chapter 6-3
n57
Setting range
Set Values
30 to 200 (%)
Stall Prevention during Operation Changes during operation
Default setting 160
No
Unit of setting
1%
• This function will decrease the output frequency if the output current exceeds the set current value by a minimum of approximately 100 ms so that the Inverter will continue operating without stalling. The Inverter will increase the output frequency to return to the set frequency reference level when the output current is less than the set value.
• The Inverter accelerates or decelerates the output frequency according to the preset acceleration or deceleration time. (Acceleration time 1: n16, n17 or acceleration time 2: n18, n19)
• Set the parameter as percentage based on the rated Inverter current as
100%.
• The default setting does not need any changes in normal operation.
• Decrease the set value if the capacity of the motor is smaller than that of the Inverter or the motor stalls with the default value.
The set value is normally 2 or 3 times higher than the rated current of the motor. Set this current in percentage based on the rated Inverter current as 100%.
Stall Prevention during Acceleration
Output current n57 (Stall prevention level during acceleration)
Time
Output frequency
The output frequency is controlled so that the Inverter will not stall.
Time
75
