Mitsubishi Electric FR-A700 Technical Manual page 212

(2) Base frequency [Pr. 3]
Second V/F (base frequency) [Pr. 47]
common
Third V/F (base frequency) [Pr. 113]
The base frequency indicates a frequency at the
rated torque of the motor. It is 50Hz or 60Hz for
standard motors.
To perform the switch-over operation of two (or three)
motors by one inverter, the base frequency dedicated
to one motor can be set in [Pr. 47 (Pr. 113)]. (Active
when RT(X9) signal is ON.) Set 9999 (initial value) in
[Pr. 47 (Pr. 113)] to set the same value in [Pr. 3].
For , [Pr. 113] is valid when both the RT and X9
A700
signals are ON.
The base frequency of the standard motor is
determined as follows:
1) When a new
recommended to set the base frequency to 60Hz
because 60Hz can be output even in a 50Hz
district and the motor torque may be utilized more
effectively by setting the base frequency to 60Hz
instead of 50Hz.
2) Set the base frequency to 50Hz when using the
inverter with the existing machine which is driven
by the commercial power supply in a 50Hz district.
3) Generally, setting the base frequency to higher
than 60Hz has no advantage.
4) The following depends on the whether the base
frequency has been set to 50Hz or 60H:
(a) Selection of data on the torque capability of
the standard motor used with the inverter.
(b) Rated torque value (in %) of the standard
motor corresponding to 100% torque.
If the base frequency used is other than 50Hz or
60Hz, a special motor designed to meet that base
frequency is required.
(3) Base frequency voltage [Pr. 19]
If the setting is equal to or less than the power supply
voltage, the maximum output voltage of the inverter is
the value set in [Pr. 19]. If the power supply voltage
rises, the output voltage does not exceed the set
value.
When [Pr. 19 = 9999], the maximum output voltage of
the inverter is same as power supply voltage.
When [Pr. 19 = 8888], the maximum output voltage of
the inverter is same as 95% of the power supply
voltage.
common
A700
machine is installed,
common
[Pr. 3 Base frequency]
The base frequency voltage can be utilized for the
following cases.
1) Regenerative frequencies are high (such as
continuous regeneration)
At the time of regeneration, the output voltage
may become higher than the V/F reference value,
causing an overcurrent trip due to the increase in
motor current. This can be prevented.
2) Fluctuation of power supply voltage is large.
it is
If the power supply voltage exceeds the rated
motor voltage, excessive torque or increased
motor current may cause the speed to fluctuate
greatly or the motor to overheat.
When operation is discontinued under vector control
due to failure of an encoder, etc., setting 9999 in [Pr.
80 Motor capacity] or [Pr. 81 Number of motor poles]
enables V/F control operation. Set parameters as
below when running the vector control dedicated
motor (SF-V5RU, SF-VR) under V/F control.
Motor Type
SF-V5RU-3.7kW or less
SF-V5RU-5.5kW or less
SF-V5RUH-3.7kW or
less
SF-V5RUH-5.5kW or
less
SF-VR
SF-VRH
246
PARAMETER
Power supply voltage
Output frequency (Hz)
Base frequency voltage
[Pr. 19]
Setting
170V
160V
340V
320V
160V
320V
[Pr. 19]
[Pr. 3] Setting
50Hz