Adjustment Of The Output Torque (Current) Of The Motor; Manual Torque Boost (Pr. 0, Pr. 46) - Mitsubishi Electric FR-E720-008 Instruction Manual

4.4

Adjustment of the output torque (current) of the motor

Purpose
Set starting torque manually
Automatically control output current
according to load
Compensate for motor slip to secure
low-speed torque
Limit output current to prevent
inverter trip
4.4.1

Manual torque boost (Pr. 0, Pr. 46)

You can compensate for a voltage drop in the low-frequency range to improve motor torque reduction in the low-speed range.
Motor torque in the low-frequency range can be adjusted to the load to increase the starting motor torque.
Two kinds of start torque boosts can be changed by switching between terminals.
Parameter
Name
Number
0 Torque boost
Second torque
46 ∗
boost
∗ The above parameters can be set when Pr. 160 User group read selection = "0". (Refer to page 187)
(1) Starting torque adjustment
On the assumption that Pr. 19 Base frequency voltage is 100%, set
the output voltage at 0Hz in % to Pr. 0 (Pr. 46).
Adjust the parameter little by little (about 0.5%), and check the
motor status each time. If the setting is too large, the motor will
overheat. The guideline is about 10% at the greatest.
(2) Set two kinds of torque boosts (RT signal, Pr. 46)
When you want to change torque boost according to applications, switch multiple motors with one inverter, etc., use Second
torque boost.
Pr. 46 Second torque boost is valid when the RT signal is ON.
For the terminal used for RT signal input, set "3" in any of Pr. 178 to Pr. 184 (input terminal function selection) to assign the function.
REMARKS
The RT signal acts as the second function selection signal and makes the other second functions valid. (Refer to page 141)

Adjustment of the output torque (current) of the motor

Parameter that should be Set
Manual torque boost
Advanced magnetic flux vector
control,
General-purpose magnetic flux
vector control
Slip compensation (V/F control
and General-purpose magnetic
flux vector control only)
Stall prevention operation
V/F V/F V/F
Initial Value
FR-E720-008(SC) to 050(SC)
FR-E740-016(SC) and 026(SC)
FR-E720S-008 to 050
FR-E710W-008 to 050
FR-E720-080(SC) to 175(SC)
FR-E740-040(SC) to 095(SC)
FR-E720S-080 and 110
FR-E720-240(SC) and 330(SC)
FR-E740-120(SC) and 170(SC)
FR-E720-470(SC) and 600(SC)
FR-E740-230(SC) and 300(SC)
9999
Pr. 0, Pr. 46
Pr. 71, Pr. 80, Pr. 81, Pr. 89,
Pr. 90, Pr. 450, Pr. 800
Pr. 245 to Pr. 247
Pr. 22, Pr. 23, Pr. 66, Pr. 156,
Pr. 157
Setting
Range
6%
4% 0 to 30% Set the output voltage at 0Hz as %.
3%
2%
Set the torque boost when the RT
0 to 30%
signal is ON.
9999 Without second torque boost
100%
Pr. 0
Setting range
Pr. 46
0
Output frequency (Hz)
Refer to Page
83
85, 88
90
91
Description
Base frequency
4
83