A shipboard transformer is a shore transformer with a harder life. The electrical design is broadly the same; what changes is everything around it, and most of the design decisions follow from the environment rather than from the load.
Environmental design
The starting point is a list of what the installation does to the equipment, because each item drives a different part of the design.
- Vibration and shock. Engines, propellers and hull motion load the structure continuously, and heavy seas add shock. The core and coil assembly is clamped and braced, and mounting feet are dimensioned for shipboard foundation practice.
- Salt spray and humidity. Airborne salt reaches windings, terminals, fasteners and coatings. The response is a sealed insulation system, corrosion-resistant fixings, and coatings specified for marine exposure.
- Ambient temperature. Machinery spaces run hot, and the insulation system rating has to be set against that ambient rather than against a shore standard.
- Inclination. The unit keeps working while the vessel heels and trims. Cooling paths must stay effective at the angles the vessel is surveyed for.
Mechanical design
Mechanical design carries more weight on board than it does ashore, because the loads are continuous rather than occasional.
- Core and winding construction braced so that conductor movement is prevented under short-circuit force as well as vibration.
- Flexible connections where thermal expansion and movement would otherwise load a rigid joint.
- Resilient mounts or vibration isolators where noise limits apply, particularly near accommodation spaces.
- Reinforced mounting structure with weight positioned to suit the vessel rather than the shop floor.
Electrical design
The electrical side covers the items that also appear on a shore specification, plus one that is specific to modern vessels.
- Insulation system selected for the ambient temperature and the expected service life.
- Conductor sizing that accounts for the actual duty cycle and the cooling available.
- Winding design and impedance chosen against the fault level at the point of installation.
- Insulation coordination between the transformer and the protection scheme.
- Harmonic loading from non-linear loads, particularly the variable frequency drives used for propulsion, thrusters and pumps. A supply rich in harmonics raises winding loss and heating.
Why it is worth settling early
Most of these decisions are cheap at specification stage and expensive later. Inclination limits, noise targets and harmonic content all have to be known before the design is frozen, because each one changes the core, the winding or the enclosure. Once the shipyard drawing is issued, the dimensions and termination positions are usually fixed.
Send the vessel requirements and the space available, and we will come back on configuration. See the ship transformer range, or contact us.
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