Exam Question

The physical basis of transformer is mutual induction between two circuits linked by a common magnetic flux. In its simplest form, it consists of two inductive coils which are electrically separated but magnetically linked through a path of low reluctance called core. The two coils posses high mutual inductance. If one coil is connected to a source of alternating voltage, an alternating flux is set up in the laminated core, most of which are linked with other coil in which it produces mutually induced emf according Faraday’s laws of electromagnetic induction. If the secondary coil circuit is closed, a current flows in it and so electric energy is transferred from first coil called Primary to second coil called secondary. Hence transformer transfer electric power from one circuit to another by electromagnetic induction without changing frequency.
(b) No 1/2 LV Main Transformer: These are usually 440V/220V, 3 phase 350 KVA delta-delta transformers. These transformers are used for lighting supply, bridge equipments, sockets in accommodation area and instrumentation requires in engine control.
Emergency Transformer: These are usually 440/220V, 1 phase x 4 sets 120kVA transformers. These transformers are used for emergency supply for equipments for the purpose of safe navigation and safety of ship in emergency situation from emergency switchboard.
Forecastle Transformer: These are usually 440/220V, 3 Phase, 30kVA transformer. These are used for low voltage supply in forecastle area like foremast navigational lighting, forecastle area upper deck lighting and various low voltage supply inside forecastle store.