Adjusting The Output Torque (Current) Of The Motor; Torque Limit (Pr.22, Pr.48, Pr.148, Pr.149, Pr.156, Pr.157) - Mitsubishi Electric FR-E700EX Instruction Manual

4.6

Adjusting the output torque (current) of the motor

Purpose
To limit the output current to avoid
tripping of the drive unit
To improve the torque in low-speed
range
4.6.1

Torque limit (Pr.22, Pr.48, Pr.148, Pr.149, Pr.156, Pr.157)

This function monitors the output current and automatically changes the rotation speed to prevent the drive unit to trip
due to overcurrent.
Parameter
Name
number
22
Torque limit level
Second torque limit
48
level
Torque limit level at
148
0mA input
Torque limit level at
149
20mA input
156 Torque limit selection
157 OL signal output timer
The above parameters can be set when Pr.160 Extended function display selection = "0". (Refer to page 182)
 This parameter allows its setting to be changed during operation in any operation mode even if "0" (initial value) is set in Pr.77 Parameter write selection.
.......Specifications differ according to the date assembled. Refer to page 316 to check the SERIAL number.
(1) Block diagram
Pr.22
RT=OFF
Pr.48
RT=ON
(2) Setting the torque limit level (Pr.22)
Pr.22
Constant
speed
OL
Torque limit example
NOTE
 If an overload status lasts long, a drive unit trip (e.g. electronic thermal relay function (E.THM)) may occur.
 If the speed drops to 18r/min or lower due to the torque limit operation and stays there for 3s, the fault indication
(E.OLT) appears, and the drive unit outputs are shut off.

Adjusting the output torque (current) of the motor

Torque limit operation
PM control torque boost
Initial value
0.75K 1.5K or
or lower higher
200% 150%
9999
150%
200%
0 0 to 31, 100, 101
0s
Pr.22=9999
Pr.22 (Pr.48)=0
Pr.22 (Pr.48)
= 0.1 to 200%
 If the output torque (current equivalent to the torque) exceeds
the current level for the torque limit operation, the output torque
Output torque
is limited by adjusting the output frequency. The torque limit
operation level in such a case is based on the rating torque of
the motor.
Rotation speed
 Torque limit operation stops acceleration (makes deceleration)
during acceleration, makes deceleration during constant speed,
and stops deceleration during deceleration.
Time
 When torque limit operation is performed, the OL signal is
output.
Parameter to set
Pr.22, Pr.48, Pr.148, Pr.149,
Pr.156, Pr.157
Pr.785
Setting range
0 Torque limit operation becomes invalid.
The current value at which torque limit operation
0.1 to 200%
will be started.
9999 Torque limit level for analog input
0 Torque limit operation becomes invalid.
0.1 to 200% The second torque limit operation level.
9999 Same as Pr.22
0 to 200%
The torque limit operation level can be changed
by the analog signal input to the terminal 4.
0 to 200%
Select whether torque limit will be performed or
not.
The output start time of the OL signal output
0 to 25s
when torque limit is activated.
9999 Without the OL signal output
Torque limit level using analog input (terminal 4)
Torque limit operation becomes invalid
Torque limit level
Refer to page
111
114
Description
111
4