Lenze 8400 motec - Manual (Page 101)

Lenze · 8400 motec · Reference manual · DMS 4.1 EN · 08/2013 · TD05 101
5 Motor control (MCTRL)
5.5 V/f characteristic control (VFCplus)
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5.5.3.1 Adapting the V/f base frequency
The V/f base frequency ( C00015 ) 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 C00015 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 C00015 , it may be required to adapt the reference speed ( C00011 )
to traverse the entire speed range of the motor.
• As a typical value, the V/f base frequency ( C00015 ) is set to the value of the rated motor
frequency ( C00089 ) for standard applications and corresponds to the data on the motor
nameplate.
• Reference voltage for the V/f base frequency is the rated motor voltage ( C00090 ) according 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.
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