Which of the following conditions are necessary to connect an alternator into the bus-bar grid.
1. Same terminal voltage.
2. Same prime mover speed.
3. Same phase sequence.
4. Same frequency.
1
Only 1, 2 and 3
2
Only 1, 3 and 4
3
Only 2, 3 and 4
4
1, 2, 3 and 4