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Adjustment of the output torque (current) of the motor
5.6.5
Stall prevention operation (Pr. 22, Pr. 23, Pr. 48, Pr. 66, Pr. 156, Pr. 157, Pr. 277)
This function monitors the output current and automatically changes the output frequency to prevent the inverter from
coming to trip due to overcurrent, overvoltage, etc. In addition, simple torque limit which limits the output torque to the
predetermined value can be selected.
It can also limit stall prevention and fast-response current limit operation during acceleration/deceleration, driving or
regeneration.
Stall prevention
If the output current exceeds the stall prevention operation level, the output frequency of the inverter is
automatically varied to reduce the output current.
Fast-response current limit
If the current exceeds the limit value, the output of the inverter is shut off to prevent an overcurrent.
Torque limit
The inverter output frequency is controlled so that the output torque (torque current) will not exceed the stall
prevention operation level (motor rated torque is referenced).
Parameter
Number
Stall prevention operation
22∗
level
Stall prevention
operation level
23
compensation factor
at double speed
Second stall prevention
48
operation current
Stall prevention
66
operation reduction
starting frequency
Stall prevention operation
156
selection
157
OL signal output timer
Stall prevention operation
277
current switchover
The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 197)
∗ This parameter allows its setting to be changed during operation in any operation mode even if "0 (initial value) or 1" is set in Pr. 77 Parameter write selection.
(1)
Block diagram
Pr.22
Pr.48
120
Name
Initial Value
150%
RT = OFF
RT = ON
Setting Range
0
0.1 to 200%
0 to 200%
9999
9999
0
9999
0.1 to 200%
9999
60Hz
0 to 400Hz
0
0 to 31, 100, 101
0 to 25s
0s
9999
0
0
1
= 0
Stall prevention operation invalid
+
Stall prevention operation level
0
-
Output frequency
Pr. 23, Pr. 66
Description
Stall prevention operation invalid
Set the current value to start the stall
prevention operation.
The stall operation level can be reduced
when operating at a high speed above the
rated frequency.
Constant according to Pr. 22.
Stall prevention operation invalid
Second stall prevention operation level
Same level as Pr. 22.
Set the frequency at which the stall
prevention operation level starts being
reduced.
Select whether stall prevention operation
and fast-response current limit operation
will be performed or not.
Output start time of the OL signal output
when stall prevention is activated.
Without the OL signal output
Output current is the limit level
Output torque (torque current) is the limit
level
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