Question

A 3 phase transformer has its primary connected in delta and secondary in star. Secondary to primary turns ratio per phase is 5. What would be the secondary voltage for a primary voltage of 400 V?
1. 3464 V
2. 80 V
3. 2000 V
4. 138 V

Answer 1

Correct Answer - Option 1 : 3464 V

Given primary voltage = 400 V

Primary connected in delta, hence phase voltage = line voltage = 400 V

Secondary to primary turns ration per phase = 5

Hence secondary phase voltage = 5 × 400 = 2000

Secondary line voltage = √3 × 2000 = 3464 V