Lenze 8400 BaseLine D - Manual (Page 84)

5 Motor control (MCTRL)
5.4 V/f characteristic control (VFCplus)
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Lenze · 8400 BaseLine D · Reference manual · DMS 5.5 EN · 01/2014 · TD05
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5.4.3.1 Adapting the V/f base frequency
The V/f base frequency ( C015 ) 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 C015 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 C015 , it may be required to adapt the reference speed ( C011 ) to tra-
verse the entire speed range of the motor.
• In standard applications, the V/f base frequency ( C015 ) is set to the value of the rated motor fre-
quency ( C089 ) 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 ( C090 ) 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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