Lenze i950 Series, Manual

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13.4.10 Flying restart circuit
The "flying restart" function serves as a protective function against high compensation cur-
rents. High compensation currents can occur in the V/f characteristic control if the drive is not
at standstill at the time the inverter is enabled. The "flying restart" function detects the motor
speed by means of a test current and uses this information to define the frequency setpoint.
CAUTION!
If the "flying restart" function is deactivated and the inverter is not enabled at standstill, the
output voltage and the output frequency do not match the current motor speed.
High compensation currents may flow! First the drive is braked towards 0 Hz to be then accel-
erated again!
▶
Ensure that the drive is at standstill before the inverter is enabled.
Flying restart process
If this function is active, the flying restart process starts after the inverter is enabled.
1
.
The inverter reports the started flying restart process to the Controller via bit 8 in the
Lenze status word 0x2831 .
2
.
If a speed is found, it is reported to the Controller via bit 9 in the Lenze status word.
3
.
The Controller reports to the inverter via bit 0 in the Lenze control word 0x2830 that the
detected speed has been accepted. As long as this is not the case, no further flying restart
process is possible.
0x2BA6
0x2831
0x2831
0x2830
Bit 0: Flying restart acknowledge
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OperationEnabled
Bit 8: Flying restart running
Bit 9: Flying restart ready
Found velocity
Parameter setting
The flying restart algorithm needs a motor voltage as exact as possible. Thus, a
previous detection of the inverter error characteristic is absolutely necessary.
Compensate inverter influence to output voltage In addition to the exact motor
voltage, a detailed knowledge of the stator resistance is required. If the flying
restart process does not work as desired, slightly adapt the setting of the stator
resistance in the 0x2C01:002 object. Bit 1 in the Lenze control word 0x2830
serves to block a flying restart process.
The flying restart process involves a control loop, the controller parameter 0x2BA3 of which
must be adapted to the motor. The automatic calculation is made with the parameter
4
0x2822:022 .
The actual flying restart process can be adjusted via the following parameters:
Configuring the motor control
V/f characteristic control for asynchronous motor (VFC open loop)
Flying restart circuit
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