Q8
(a) Why is it important to maintain high efficiency of operation and low values of voltage regulation for power transformers?
(6)
(b) A 100 kVA transformer has 400 turns on the primary and 80 turns on the secondary. The primary and secondary resistances are 0.3 Ω and 0.01Ω respectively, and the corresponding leakage reactances are 1.1 Ω and 0.035 Ω respectively. The supply voltage is 2200 V. Calculate:
(i) The equivalent impedance referred to the primary circuit;
(ii) The voltage regulation and secondary terminal voltage for full load having a power factor of
(I) 0.8 lagging and
(II) 0.8 leading.
(10)
Reference Answer
### Part (a): Importance of High Efficiency and Low Voltage Regulation **(i) Importance of High Efficiency (η)** Efficiency of a transformer is defined as the ratio of output power to input power. A high efficiency is critically important for the following reasons: * **Energy Conservation and Fuel Economy:** Onboard a vessel, all electrical power is generated by diesel generators burning fuel. Transformer losses (copper losses in windings and iron losses in the core) are dissipated as heat. High efficiency implies low losses, which translates directly to reduced fuel consumption by the prime movers for the same electrical load. This results in significant operational cost savings and increased endurance.
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.