(a) Delta-star connection:
The line voltage on the primary side is given by:
Vp = √3 * Vp_ph
Vp = √3 * 1.5 kV
Vp = 2.598 kV
The secondary line voltage on no-load is given by:
Vs = 1/√3 * Vp
Vs = 1/√3 * 2.598 kV
Vs = 1.5 kV
Therefore, the secondary line voltage on no-load in a delta-star connection is 1.5 kV.
(b) Star-delta connection:
The line voltage on the primary side is the same, 2.598 kV.
The secondary line voltage on no-load is given by:
Vs = Vp / √3
Vs = 2.598 kV / √3
Vs = 1.5 kV
Therefore, the secondary line voltage on no-load in a star-delta connection is also 1.5 kV.
5. A three-phase transformer has 600 primary turns and 150 secondary turns. If
the supply voltage is 1.5 kV determine the secondary line voltage on no-load
when the windings are connected (a) delta-star, (b) star-delta.
1 answer