Parameter Function Details; Torque Boost (Pr. 0, Pr. 46, Pr. 112) - Mitsubishi Electric FR-A500 Instruction Manual

4.2 Parameter Function Details

4.2.1

Torque boost (Pr. 0, Pr. 46, Pr. 112)

Pr. 0 "torque boost"
Pr. 46 "second torque boost"
Pr. 112 "third torque boost"
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.
You can select any of the three different starting torque boosts by terminal switching.
Parameter Factory
Number Setting
0.4K, 0.75K 6%
1.5K to 3.7K 4%
0
5.5K, 7.5K 3%
11K or more 2%
46 9999
112 9999
<Setting>
Assuming that the base frequency voltage is 100%, set the 0Hz voltage in %.
A large setting will cause the motor to overheat. The guideline for maximum value is about 10%.
Pr. 46 "second torque boost" is made valid when the RT signal turns on. Pr. 112 "third torque boost" is
made valid when the X9 signal turns on. Use any of Pr. 180 to Pr. 186 to assign the terminal used for X9
signal input. (Note 5)
Note: 1. When using a constant-torque motor, change the setting of this parameter as follows:
0.4K, 0.75K...6%, 1.5K to 3.7k, 4%, 5.5K or more...2%
2. This parameter setting is ignored when Pr. 80 and Pr. 81 have been set to select the advanced
magnetic flux vector control mode.
3. When the Pr. 0 setting is either of the following values for 5.5K and 7.5K, it is automatically
changed when the Pr.71 setting is changed:
(1) When Pr. 0 setting is 3% (factory setting)
The Pr. 0 setting is changed to 2% automatically when the Pr. 71 setting is changed from
[transistorized motor selection value (0, 2 to 8, 20, 23, 24)] to [constant-torque motor
selection value (1, 13 to 18)].
(2) When Pr. 0 setting is 2%
The Pr. 0 setting is changed to 3% (factory setting) automatically when the Pr. 71 setting is
changed from [constant-torque motor selection value (1, 13 to 18)] to [transistorized motor
selection value (0, 2 to 8, 20, 23, 24)].
4. Increase the setting when the inverter-to-motor distance is long or motor torque in the low-speed
range is insufficient, for example. A too large setting may result in an overcurrent trip.
5. The RX (X9) signal acts the second (third) function select signal and the other second (third) functions
are also made valid. Refer to page 155 for Pr. 180 to Pr. 186 (input terminal function selection).
Setting Range Remarks

0 to 30%
0 to 30%, 9999 9999: Function invalid
0 to 30%, 9999 9999: Function invalid
71
PARAMETERS
Related parameters
Pr. 3 "base frequency"
Pr. 19 "base frequency voltage"
Pr. 71 "applied motor"
Pr. 80 "motor capacity"
Pr. 81 "number of motor poles"
Pr. 180 to Pr. 186
(input terminal function selection)
100%
Pr.0
Pr.46
Setting range
Pr.112
0 Output frequency (Hz) Base frequency
4