A single-phase transformer with a 2-kVA rating has a 480-V primary and a 120-V secondary. Determine the primary and secondary full-load currents of the transformer.
A single-phase transformer with a 2-kVA rating has a 480-V primary and a 120-V secondary. Determine the primary and secondary full-load currents of the transformer.
Right Answer is:
4.17 A and 16.67 A
SOLUTION
This is a single-phase transformer rated in kilovolt-amperes; therefore, the equation used to determine the full-load current for both windings is
Primary full-load current = (kVA rating × 1000) / Primary Voltage
The full-load current of the primary winding of the transformer is 4.17 amperes, and for the secondary winding, the full-load current is 16.67 amperes.
Primary full-load current = ( 2 kVA × 1000 ) / 480 V = 4.17 A
Secondary full-load current = VA rating / Secondary Voltage
Secondary full-load current = ( 2 kVA × 1000 ) / 120 V = 16.67 A