The power supply from ashore may have a different frequency and I or voltage to that of the ship’s system.
- A higher frequency will cause motors to run faster, be overloaded & overheat; a higher voltage will generally cause equipment to draw excess current & also overheat. It will also cause motors to accelerate more rapidly and this may over-stress driven loads.
- A lower voltage is generally not so serious but may cause motors to run slower & overheat, & may also cause motors to stall. If the shore supply frequency differs from the ship’s normal frequency, then, ideally, the shore supply voltage should differ in the same proportion.