70 Shipboard Electrical Power Systems
3.9 POWER RATING OF EQUIPMENT
The following applies to all equipment (electrical or mechanical) commonly found
in electrical power plants.
The electrical power ratings of generators and transformers are stated in kVA
or MVA (not in the real power kW or MW). These machines can deliver rated
voltage and rated current, but the real power delivered by the machine depends
on the power factor, which is primarily determined by the nature of the load con-
nected. We often see the electrical power plant capacity expressed in MW, since it
refers to the mechanical output rating of the prime mover, which is the dominant
investment in the power plant. Moreover, the MW rating also determines the
plant’s f