1 adapting the v/f base frequency, Adapting the v/f base frequency, Adapting the v/f base frequency ( 83) – Lenze 8400 BaseLine C User Manual
Page 83: 5motor control (mctrl)
Lenze · 8400 BaseLine C · Reference manual · DMS 1.6 EN · 01/2014 · TD05
83
5
Motor control (MCTRL)
5.4
V/f characteristic control (VFCplus)
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5.4.3.1
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.
, it may be required to adapt the reference speed (
) to tra-
verse the entire speed range of the motor.
• In standard applications, the V/f base frequency (
) is set to the value of the rated motor fre-
quency (
) as a typical value and corresponds to the data of the motor nameplate.
• Reference voltage for the V/f base frequency is the rated motor voltage (
) according to mo-
tor 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.
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