Stall Prevention Operation - Mitsubishi Electric FR-A760 Series Instruction Manual

Adjust the output torque (current) of the motor
4.8.4 Stall prevention operation (Pr. 22, Pr. 23, Pr. 48, Pr. 49, Pr. 66, Pr. 114, Pr. 115,
Pr. 148, Pr. 149, Pr. 154, Pr. 156, Pr. 157, Pr. 858, Pr. 868)
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. It can also limit stall prevention and fast-response
current limit operation during acceleration/deceleration, driving or regeneration. Invalid under real sensorless
vector control or vector control.
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.
Also the second stall prevention function can restrict the output frequency range in which the stall prevention
function is valid. (Pr. 49)
Fast-response current limit
If the current exceeds the limit value, the output of the inverter is shut off to prevent an overcurrent.
Parameter
Name
Number

Stall prevention operation

22
level

Stall prevention operation

23 level compensation factor
at double speed
Second stall prevention
48
operation current
Second stall prevention
49
operation frequency
Stall prevention operation
66
reduction starting frequency
Third stall prevention
114
operation current
Third stall prevention
115
operation frequency
Stall prevention level at 0V
148
input
Stall prevention level at
149
10V input
Voltage reduction
154 selection during stall
prevention operation
Stall prevention operation
156
selection
157 OL signal output timer
Terminal 4 function
858
assignment
Terminal 1 function
868
assignment
* When Pr. 570 Multiple rating setting ≠ "2", performing inverter reset and all parameter clear changes the initial value and setting
range. (Refer to page 143)
Pr. 22
Constant
speed
OL
Stall prevention operation example
CAUTION
⋅ If an overload status lasts long, an inverter trip (e.g. electronic thermal relay function (E.THM)) may occur.
⋅ When Pr. 156 has been set to activate the fast-response current limit (initial setting), the Pr. 22 setting should not be higher than
170%. The torque will not be developed by doing so. (When Pr. 570 = "2")
⋅ When real sensorless vector control or vector control is selected using Pr. 800 Control method selection, Pr.22 serves as torque limit level.
For the FR-A760-00061 or less, the Pr. 22 setting changes from 150% (initial value) to 200%.
138
Initial Setting
Value Range
150% *
0.1 to 400%
0 to 200% *
9999
150% *
0.1 to 220% *
0Hz 0.01 to 400Hz
60Hz 0 to 400Hz
150% *
0.1 to 220%
0Hz
0.01 to 400Hz
150% * 0 to 220% *
200% * 0 to 220% *
1
0 to 31,
0
100, 101
0 to 25s
0s
0 0, 1, 4, 9999
0 0 to 6, 9999
(1) Setting of stall prevention operation level (Pr. 22)
Output current
⋅ Set in Pr. 22 the ratio of the output current to the rated inverter current at
which stall prevention operation will be performed. Normally set 150%
(initial value).
Output frequency
⋅ Stall prevention operation stops acceleration (makes deceleration) during
acceleration, makes deceleration during constant speed, and stops
deceleration during deceleration.
Time
⋅ When stall prevention operation is performed, the OL signal is output.
0 Stall prevention operation selection becomes invalid.
Set the current value at which stall prevention operation will
be started.
The stall operation level can be reduced when operating at
a high speed above the rated frequency.
9999 Constant according to Pr. 22
0 Second stall prevention operation invalid
The second stall prevention operation level can be set.
0 Second stall prevention operation invalid
Set the frequency at which stall prevention operation of Pr.
48 is started.
9999 Pr. 48 is valid when the RT signal is on.
Set the frequency at which the stall operation level is
started to reduce.
0 Third stall prevention operation invalid
Stall prevention operation level can be changed with the X9
signal.
0 Third stall prevention operation invalid
Set the frequency at which stall prevention operation when
the X9 signal is on starts.
Stall prevention operation level can be changed by the
analog signal input to terminal 1 (terminal 4).
0 With voltage reduction
1 Without voltage reduction
You can select whether stall prevention operation and fast-
response current limit operation will be performed or not.
Set the output start time of the OL signal output when stall
prevention is activated.
9999 Without the OL signal output
By setting "4", the stall prevention operation level can be
changed with a signal to terminal 4.
By setting "4", the stall prevention operation level can be
changed with a signal to terminal 1.
V/F V/F V/F Magnetic flux Magnetic flux Magnetic flux
Description
You can select whether to use
output voltage reduction during
stall prevention operation or not.