TRANSFORMERS
WORKING PRINCIPLE -A transformer works on Faraday’s Law of Electromagnetic Induction. When an alternating voltage is applied to the primary winding, an alternating current produces a changing magnetic flux in the iron core. This changing flux links with the secondary winding and induces an EMF in it.
The basic voltage relationship is:
V₁ / V₂ = N₁ / N₂ Where:
V₁ = Primary voltage
V₂ = Secondary voltage
N₁ = Number of primary turns
N₂ = Number of secondary turns
MAIN PARTS OF A TRANSFORMER
MAGNETIC CORE – Provides a low-reluctance path for magnetic flux.
PRIMARY WINDING – Connected to the AC supply.
SECONDARY WINDING – Supplies the transformed voltage to the load.
INSULATION – Electrically separates windings and other components.
TRANSFORMER OIL – Used for insulation and cooling in oil-filled transformers.
TANK – Contains the core, windings and insulating oil.
RADIATORS – Dissipate heat from the transformer oil.
CONSERVATOR TANK – Allows expansion and contraction of transformer oil.
BREATHER – Prevents moisture from entering the conservator.
BUSHINGS – Provide insulated electrical connections through the transformer tank.
TYPES OF TRANSFORMERS
STEP-UP TRANSFORMER: Increases the output voltage.
STEP-DOWN TRANSFORMER: Decreases the output voltage.
ISOLATION TRANSFORMER: Provides electrical isolation between two circuits, normally with a 1:1 voltage ratio.
AUTO TRANSFORMER: Uses a common winding for both primary and secondary circuits.
THREE-PHASE TRANSFORMER: Used for three-phase power systems and industrial applications.
TRANSFORMER LOSSES-The main losses are:
Copper Loss – Due to resistance of primary and secondary windings.
Core/Iron Loss – Consists mainly of hysteresis and eddy-current losses.
Stray Losses – Caused by leakage flux inducing currents in surrounding metallic parts.
Dielectric Losses – Occur in the insulation.
Transformer Efficiency
Transformer efficiency is:
η = Output Power / Input Power × 100
A well-designed transformer can have very high efficiency because it has no rotating or moving parts.
Applications in Ships Transformers are commonly used onboard ships for:
- Stepping down 440 V to 220 V or 110 V
- Supplying lighting systems
- Control and instrumentation circuits
- Navigation equipment
- Communication systems
- Battery chargers
- Emergency electrical systems
- Isolation of sensitive electrical equipment
