Adjustment Of The Output Torque (Current) Of The Motor; Manual Torque Boost (Pr. 0, Pr. 46) - Mitsubishi Electric FR-F720-0.75K to 110K Instruction Manual

Adjustment of the output torque (current) of the motor

4.3 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
4.3.1

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.
The starting torque boost can be changed by switching terminals.
Parameter
Name
Number
0 Torque boost
Second torque
46
*1
boost
*1 They can be set when Pr. 160 User group read selection = "0". (Refer to page 175.)
100%
Output
voltage
Pr.0
Setting
Pr.46
range
0
(2) Set multiple torque boost (RT signal, Pr. 46)
⋅ Use the second torque boost when changing the torque boost according to application or when using multiple
motors by switching between them by one inverter.
⋅ Pr. 46 Second torque boost is valid when the RT signal turns on.
REMARKS
⋅ The RT signal acts as the second function selection signal and makes the other second functions valid. (Refer to page 117)
⋅ The RT signal is assigned to the RT terminal in the default setting. By setting "3" to any of Pr. 178 to Pr. 189 (Input terminal function
selection), you can assign the RT signal to the other terminal.
CAUTION
⋅ Increase the setting when the distance between the inverter and motor is long or when motor torque is insufficient in the low-
speed range. If the setting is too large, an overcurrent trip may occur.
⋅ The Pr. 0 and Pr. 46 settings are valid only when V/F control is selected.
⋅ When using the inverter dedicated motor (constant-torque motor) with the 5.5K or 7.5K, set the torque boost value to 2%. If the
initial set Pr. 71 value is changed to the setting for use with a constant-torque motor, the Pr. 0 setting changes to the
corresponding value in above.
⋅ Changing the terminal assignment using Pr. 178 to Pr. 189 (input terminal function selection) may affect the other functions. Please
make setting after confirming the function of each terminal.
♦ Parameters referred to ♦
Pr. 3 Base frequency, Pr. 19 Base frequency voltage
Pr. 71 Applied motor Refer to page 105
Pr. 80 Motor capacity Refer to page 75
Pr. 178 to Pr. 189 (Input terminal function selection)
74
Manual torque boost
Simple magnetic flux
vector control
Slip compensation
Stall prevention operation
Initial Value
0.75K
1.5K to 3.7K
5.5K, 7.5K
11K to 37K
45K, 55K
75K or more
9999
Output Base
frequency
frequency
(Hz)
Refer to page 84
Refer to page 115
Parameter that must be Set
Pr. 71, Pr. 80, Pr. 90
Pr. 245 to Pr. 247
Pr. 22, Pr. 23, Pr. 66,
Pr. 154, Pr. 156, Pr. 157
Setting
Range
6%
4%
3%
0 to 30%
2%
1.5%
1%
0 to 30%
9999
(1) Starting torque adjustment
⋅ On the assumption that Pr. 19 Base frequency voltage is
100%, set the output voltage at 0Hz in % in 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.
Refer to Page
Pr. 0, Pr. 46
Description
Set the output voltage at 0Hz as %.
Set the torque boost value when the
RT signal is on.
Without second torque boost
74
75
76
77