8400 motec | Software Manual
Motor control (MCTRL)
V/f characteristic control (VFCplus)
72
L
Firmware
≤
02.00 - DMS 2.1 EN - 03/2011
5.5.3.1
Adapting the V/f base frequency
The V/f base frequency (
) determines the slope of the V/f characteristic and has
considerable influence on the current, torque, and power performance of the motor.
The setting in
applies to all permitted mains voltages.
Mains fluctuations or fluctuations of the DC-bus voltage (operation in generator mode)
do not need to be considered when the V/f base frequency is set. They are
automatically compensated for by the internal mains voltage compensation of the
device.
Depending on the setting in
, it may be required to adapt the reference speed
(
) to traverse the entire speed range of the motor.
As a typical value, the V/f base frequency (
) is set to the value of the rated motor
frequency (
) for standard applications and corresponds to the data on the mo-
tor nameplate.
Reference voltage for the V/f base frequency is the rated motor voltage (
) ac-
cording to the motor nameplate.
Note!
87-Hz operation
4-pole asynchronous motors which are designed for a rated frequency of f = 50
Hz in star connection can be operated in delta connection when being constantly
excited up to f = 87 Hz.
• Advantages:
– Higher speed-setting range
– 73% higher power output in case of standard motors
• Motor current and motor power increase by the factor
.
• The field weakening range starts above 87 Hz.
• Generally, this process can also be used with motors which have different
numbers of pole pairs. In case of 2-pole asynchronous motors, the mechanical
limit speed must be maintained.
3
Содержание 8400 motec Series
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