ABB ACS560 Firmware Manual page 129

Example of PFC autochange with auxiliary pumps in a 3-pump constant pressure
water supply application:
Pump 1 - connected to VSD motor
Pump 2 - connected to auxiliary motor 1
Pump 3 - connected to auxiliary motor 2
Flow consumption versus pump status
Consumption
Low
Normal
↓
↓
Normal
VSD
DOL
Off
2. Autochange PFC with all the motors
In this mode, all motors involves in the autochange. VSD motor moves to next
Pump 1
VSD
VSD
VSD
VSD
VSD
Variable Speed Drive (yellow colour connecting line in the figure).
Controlled by drive, tuning the output speed according to PID control.
Direct On Line (red colour connecting line in the figure). Pump is running
at fixed motor nominal speed.
Off-line. Pump stops.
Pump 2
Off
DOL
Off
DOL
Off
Control macros 129
Pump 3
Off
Off
DOL
Off
DOL