Lenze 8200 Frequency inverters - Manual (Page 162)

Configuration
8200SHB0199 7-25
Function when
C014 = -2-, -3- Load-independent boost of the motor voltage in the field frequency range below the V/f-rated
frequency. Thus, the torque performance of the inverter drive can be optimised.
Adjustment It is absolutely necessary to adapt C016 to the asynchronous motor used. Otherwise, the motor
might be destroyed by overtemperature or the inverter might be driven with overcurrent.
1.Operate the motor in idle running with a slip frequency of f
d
 :
- P
mot
$ 7.5 kW: f
d
 5 Hz
- P
mot
 7.5 kW: f
d
 2 Hz
Slip-frequency calculation
f
s
 f
dr
ô
n
Nsyn
Å n
r
n
Nsyn
n
Nsyn

f
dr
ô 60
p
f
s
Slip frequency
f
dr
Rated frequency to motor nameplate [Hz]
n
Nsyn
Synchronous motor speed [min -1 ]
n
r
Rated speed to motor nameplate [min -1 ]
p Number of pole pairs
2.Increase V
min
until the following motor current is reached:
- Motor in short-term operation at 0 Hz ˆ f
d
ˆ 25 Hz:
Self-ventilated motors: I
motor
ˆ I
r motor
Forced-ventilated motors: I
motor
ˆ I
r motor
- Motor in continuous operation at 0 Hz ˆ f
d
ˆ 25 Hz:
Self-ventilated motors: I
motor
ˆ 0.8 k I
r motor
Forced-ventilated motors: I
motor
ˆ I
r motor
Important The change from V/f-characteristic control to motor-current control should only be carried out when
the controller is inhibited.
Observe the thermal performance of the connected asynchronous motor at low field frequencies
when adjusting it:
- Usually, standard asynchronous motors with insulation class B can be driven for a short time with
rated frequency within the frequency range 0 Hz
ˆ f
d
ˆ 25 Hz.
- Contact the manufacturer for exact setting values for the max. permissible motor current in the
lower frequency range of self-ventilated motors.
Function when C014 = -4- V
min
is not effective when using the control mode ”motor current control”.
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