ABB COM600 Owner's/Operator's Manual page 18

COM600 3.3
18
Station Automation COM600
Operator's Manual
Figure 3.6.2-1 Switch Device Control dialog
Three-state switch
A Three-state switch combines two disconnectors into one visible symbol and control
dialog. One of the disconnectors is connected to earth, the other (main) to the switch
gear.
The Three-state switch can be closed (main disconnector closed), opened and earthed
(earth disconnector closed). It is not possible to go directly from closed to earthed state,
or the other way around, the switch must always be opened first.
When the switch is open it can be either closed or earthed. It is also not possible to control
the switch when the state is bad or intermediate.
1MRS756705
switch_control.bmp