51
2-8-12 Motor Stall Prevention Function
Item name
Constant to be set
Factory preset
Operation level for stall prevention during
acceleration
No. 30
170%
Operation level for stall prevention during run-
ning
No. 31
160%
Stall prevention during deceleration
No. 20
0000
Automatically adjusts output frequency according to the load so as
to continue operation of the machine without stalling the motor.
Stall Prevention During Acceleration
Stall Prevention During Running
Time
Time
Output freq.
Motor current
Reduces speed to prevent motor over-
load
No. 31
Suppresses acceleration rate
during this time to prevent stall.
Motor current
Time
Time
output freq.
No. 30
Set “1” for connecting braking resistor unit.
No. 20 = 0xxx
0: Stall prevention during deceleration enabled
1: Stall prevention during deceleration disabled
When using a high-speed motor that uses the constant power out-
put area (with frequency of higher than the maximum voltage fre-
quency), the stall prevention operation level must be lowered.
Voltage
Frequency
Constant power
output area
Frequency
Operation
level
V/F Pattern
Constant power
output area
Set the third digit of No. 46 to “1.” The Inverter will automatically
lower the operating level to ensure stable operation in the constant
power output area.
Stall Prevention During
Deceleration
Automatic Drop of
Stall Prevention
Operation Level During
Acceleration in
Constant Power
Output Area
Description of Functions and Constants
Section 2-8
