Consider a single-phase three-winding transformer with the primary excited winding of \(N_{1}\) turns carrying a current \(I_{1}\) and two secondary windings of \(N_{2}\) and \(N_{3}\) turns, delivering currents of \(I_{2}\) and \(I_{3}\) respectively. For an ideal case, how are the ampere-turns balanced?

(a) \(N_{1} I_{1}=N_{2} I_{2}-N_{3} I_{3}\)

(b) \(N_{1} I_{1}=N_{2} I_{2}+N_{3} I_{3}\)

(c) \(N_{1} I_{1}=-\left(N_{2} I_{2}-N_{3} I_{3}ight)\)