ABB ACS560 - Page 129

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