Stall Prevention - Mitsubishi Electric FR-F740 EC Instruction Manual

Motor torque
6.2.4 Stall prevention operation
(Pr. 22, Pr. 23, Pr. 48, Pr. 49, Pr. 66, Pr. 148, Pr. 149, Pr. 154, Pr. 156, Pr. 157)
This function monitors the output current and automatically changes the output frequency to
prevent the inverter from coming to an alarm stop due to overcurrent, over voltage, etc. It can
also limit stall prevention and fast-response current limit operation during acceleration/decel-
eration, 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.
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.
Pr.
Name
No.
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
Stall prevention level at 0V
148
input.
Stall prevention level at 10V
149
input.
Voltage reduction selection
154
during stall prevention
operation
Stall prevention operation
156
selection
157
OL signal output timer
The above parameters can be set when Pr. 160 = 0.
When Pr. 570 "Multiple rating setting" = 1, performing parameter clear changes the initial
value and setting range.
The above 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.
6 - 44
Initial Setting
Description
Value Range
Stall prevention operation selection
0
becomes invalid.
110% Set the current value at which stall
0.1–120%
prevention operation will be started.
9999 Analog variable
The stall operation level can be
reduced when operating at a high
0–150%
9999
speed above the rated frequency.
9999 Constant according to Pr. 22
Second stall prevention operation
0
invalid
110%
The second stall prevention operation
0.1–120%
level can be set.
Second stall prevention operation
0
invalid
Set the frequency at which stall pre-
0Hz 0.01–400Hz
vention operation of Pr. 48 is started.
Pr. 48 is valid when the RT signal is
9999
on.
Set the frequency at which the stall
50Hz 0–400Hz
operation level is started to reduce.
110%
0–120% Stall prevention operation level can
be changed by the analog signal input
to terminal 1.
120%
0–120%
With voltage
0
reduction
1
Without volt-
1
age reduction
You can select whether stall preven-
0–31/ tion operation and fast-response cur-
0
100/101 rent limit operation will be performed
or not.
Set the output start time of the OL
0–25s signal output when stall prevention is
0s
activated.
9999 Without the OL signal output
Parameters referred to
73
178–189
190–196
570
You can select
whether to use out-
put voltage reduc-
tion during stall
prevention opera-
tion or not.
Parameter
Refer to
Section
Analog input 6.15.1
selection
Input terminal 6.9.1
function selection
Output terminal 6.9.5
function selection
Multiple rating 6.2.5
setting