INVT Goodrive350-19 Series Operation Manual page 119

Goodrive350-19 Series VFD for Crane Commissioning guidelines
High-speed
brake
Fan
Fan
Lifting motor 1 Lifting motor 2
Low-speed Low-speed
brake brake
Figure 5-18 Mechanical structure 1
In general, if multiple VFDs control multiple motors through belt connection, it is considered as flexible
connection (or soft connection). When flexible connection is applied, generally, the slave adopts the
speed control mode, and then the droop function is used to achieve better power balance
performance. Therefore, in the terminal master/slave mode, master/slave mode a is recommended; in
the CAN communication master/slave mode, master/slave mode 0 is recommended.
In general, if multiple VFDs control multiple motors through shaft, gear, or chain connection, it is
considered as rigid connection (or hard connection). When rigid connection is applied, generally, the
slave adopts the torque control mode for better power balance performance. Therefore, in the
terminal master/slave mode, master/slave mode b is recommended; in the CAN communication
master/slave mode, master/slave mode 1 is recommended.
2. Master/slave speed synchronization
Master/slave speed synchronization is used for the speed synchronization between two motors.
Using the function requires that both motors have the encoder installed, and the VFD has the encoder
pulse counting function. The mechanical structure is shown in Figure 5-19.
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