Mitsubishi Electric FR-A720-0.4K Instruction Manual page 115

Speed control by Real sensorless vector
control, vector control
(9) Trip when torque limit is activated (Pr. 874 )
Torque
Pr. 874
Output torque
Output
frequency
Pr. 865
Start
signal
(STF)
Fault
output
REMARKS
⋅ If the frequency has fallen to 0.5Hz by stall prevention operation and remains for 3s under V/F control and Advanced magnetic
flux vector control, a fault (E.OLT) appears and trips the inverter. In this case, this function is activated regardless of Pr. 874 .
This fault is not provided under torque control.
(10) Stall prevention operation signal output and output timing adjustment (OL signal, Pr. 157)
⋅ When the output torque exceeds the torque limit level and torque limit is activated, the stall prevention operation
signal (OL signal) turns on for longer than 100ms. When the output torque falls to or below the torque limit level, the
output signal turns off.
⋅ Use Pr. 157 OL signal output timer to set whether the OL signal is output immediately or after a preset period of time.
⋅ This operation is also performed when the regeneration avoidance function
Pr. 157 Setting
0
Output immediately
(initial value)
0.1 to 25 Output after the set time (s) has elapsed
9999 Not output
REMARKS
⋅ The OL signal is assigned to the terminal OL in the initial setting. The OL signal can also be assigned to the other terminal by
setting "3 (positive logic) or 103 (negative logic)" to any of Pr. 190 to Pr. 196 (output terminal function selection).
CAUTION
· When speed control is performed, a fault (E.OLT) is displayed and the inverter output is stopped if frequency drops to the Pr.
865 Low speed detection (initial value is 1.5Hz) setting by torque limit operation and the output torque exceeds Pr. 874 OLT level
setting (initial value is 150%) setting and remains for more than 3s.
· When terminal assignment is changed using Pr. 190 to Pr. 196 (output terminal function selection), the other functions may be
affected. Please set parameters after confirming the function of each terminal.
♦Parameters referred to♦
⋅ Pr. 22 Stall prevention operation level
⋅ Pr. 178 to Pr. 189 (input terminal function selection)
⋅ Pr. 840 Torque bias selection
⋅ Pr. 865 Low speed detection
104
Torque limit
Time
Time
3s
E.OLT occurrence
Description
Refer to page 152
Refer to page 231
Refer to page 114
Refer to page 246
⋅ This function can cause a trip if the torque limit is activated
to stall the motor.
⋅ The motor stalls if the torque limit is activated under a high
load applied during speed control or position control. At this
time, if the motor speed is lower than the speed set in Pr.
865 Low speed detection and also the output torque exceeds
the level set in Pr. 874 OLT level setting for 3s, it is regarded
as a stop effected by stall prevention and E. OLT is output,
resulting in a trip.
Overload state
(OL operation)
OL output signal
(overvoltage stall) is executed.
Pr.157 Set time(s)