8.17.7 Synchronous Transfer Operation For Induction Motors Down Transfer (L29)
Down Transfer of Induction Motor
Down transfer is used to transfer a motor from the line to the drive. With NXGPro+ control, the
drive monitors the output voltage before locking-in to the motor frequency via the spinning load
algorithm. For the drive to perform this action, the VFD contactor must be closed at the
beginning of the down transfer sequence while the drive output is still disabled. The drive is
capable of locking-in within a few milliseconds. The drive then raises the output torque current
before indicating that it is ready to accept the motor and open the line contactor.
The procedures for down transfer setup are carried out during the commissioning process.
8.17.8 Synchronous Transfer Operation For Induction Motors Synchronous Transfer
with Multiple Motors (L29)
Synchronous Transfer with Multiple Motors
The drive can control multiple motors using synchronous transfer methodology. In such
applications, the drive sequentially controls a series of motors, one motor at a time.
Figure 8-10 Multiple Motor Synchronous Transfer
Figure Multiple Motor Synchronous Transfer shows the VFD conguration for synchronous
transfer of a two motor implementation. A PLC must be used for multiple motor synchronous
transfer applications. The PLC and its logic can be supplied by Siemens to coordinate the transfer
sequence and also control the switchgear. In addition, motor protection relays are
recommended since the VFD cannot protect a motor operating from the line.
Advanced Operating Functions
8.17 Synchronous Transfer
NXGPro+ Control Manual
Operating Manual, A5E50491925A 263
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