Example: Step Down Transformer

Problem Statement

Given a 48 kVA, 480/240 V/V step down transformer operating at rated load with a power factor of 0.7 (lag), determine the efficiency and voltage regulation.

Given: $R_{L}~=~0.2~\Omega ,~~X_{L}~=~0.6~\Omega ,~~R_{H}~=~0.8~\Omega ,~~X_{H}~=~1.6~\Omega ,~~R_{cH}~=~3.2~k\Omega ,~~H_{cH}~=~1.2~k\Omega$

• this problem is from EMEC EXAM 1, Winter 08 by legendary Dr. Cross