Three single-phase, 10-kVA, 2400/120-V, 60- Hz transformers are connected to form a three phase, 4160/208-V transformer bank. Each of the single-phase transformers has an equivalent series impedance of 10 + j25 Ω referred to the high-voltage side. The transformer bank is said to deliver 27 kW at 208 V and 0.9 power factor leading.
(a) Draw a schematic diagram of transformer connections, and develop a per-phase equivalent circuit.
(b) Determine the primary current, primary voltage, and power factor.
(c) Compute the voltage regulation.