Mitsubishi Electric FR-F740 EC Instruction Manual page 209

Parameter
Set multiple base frequencies (Pr. 47)
Use the second base frequency when you want to change the base frequency, e.g. when using
multiple motors by switching between them by one inverter.
Pr. 47 "Second V/f (base frequency)" is valid when the RT signal is on.
NOTES
The RT signal acts as the second function selection signal and makes the other second
functions valid.
In the initial setting, the RT signal is assigned to the RT terminal. 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.
Base frequency voltage setting (Pr. 19)
Use Pr. 19 "Base frequency voltage" to set the base voltage (e.g. rated motor voltage). If the set-
ting is less than the power supply voltage, the maximum output voltage of the inverter is as set
in Pr. 19.
Pr. 19 can be utilized in the following cases:
● When regeneration frequency is high (e.g. continuous regeneration)
During regeneration, the output voltage becomes higher than the reference and may cause
an overcurrent trip (E.OC ) due to an increased motor current.
● When power supply voltage variation is large
When the power supply voltage exceeds the rated voltage of the motor, speed variation or
motor overheat may be caused by excessive torque or increased motor current.
● For special settings (87Hz function, special motors, field weakening range).
Pr. 19 can also be set to a value above the power supply voltage when operating motors
with special windings, in 87Hz mode or for field weakening operation with a specific output
voltage. The inverter will then use a V/f pattern the rise of which is defined by Pr. 3 and Pr.
19. However, the actual effective output voltage cannot be higher than the power supply
voltage and is thus limited to this maximum value.
NOTES
When Pr. 71 "Applied motor" is set to "2" (adjustable 5 points V/F characteristic), the Pr. 47
setting becomes invalid. In addition, you cannot set "8888" or "9999" in Pr. 19.
Note that the output voltage of the inverter cannot exceed the power supply voltage.
FR-F700 EC
Set V/f pattern
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