Agree with FunctionedSatis, latching in the batt s/w just results in the (amber) gen. drive lights, if the standby power s/w is selected to batt. the static inverter will be powered, and power the standby a.c. bus but it's not normally used!
With engines running the electrical power is split left and right with the BTB's open. (all switches normally left latched in.)
Gen. failure results in amber drive light and amber cross on synoptic (‘drive’ shows for low oil pressure and /or failure), the BTB's will close and the remaining gen. will supply power to busses. If one of the BTB's (also) fails to close the backup gen. comes online to supply the now dead transfer bus. The main bus remains dead as does the affected utility bus.
Unlatching the gen. control s/w gives an amber cross on the 'gen control' on the synoptic.
Q3 Only if it is unlatched or the field is tripped. Just cycling the switch will bring it back online. Usually only occurs following something like a gen. change or engine change.
Also the BAT s/w only has an amber OFF light if selected off and there is AC power on the a/c.
Standby Power Switch
The standby power switch has these three positions:
OFF - AUTO - BAT (momentary).
On the ground, the off position makes the static inverter stay off. In the air, the off position has no effect.
The AUTO position puts the standby electrical power system under the ELMS control. A guard over the switch moves it to AUTO. The switch is normally left in AUTO.
To use the battery position (BAT). Push the battery switch on then open the guard and select BAT (push on release springs back to AUTO). With no AC power on the a/c, the switch in BAT turns the static inverter on and it powers the standby AC bus.
I think thats correct I had to sit and draw it out! 