Ever since AC generation and distribution has been introduced on a large scale on ships around 1950, there has been debate about the type of distribution system. The main focus wit... Read more
Naturally, all lamps are designed to produce their rated luminous output at their rated voltage. An overvoltage on an incandescent lamp produces a brighter and whiter light because... Read more
Induction motors are fitted with ball and or roller bearings. These bearings are robust and reliable and should give very little trouble provided they are properly fitted, kept abs... Read more
Look at the stator windings for damaged insulation caused by careless replacement of the rotor into the stator. Discoloured insulation is an indication that the winding has been ov... Read more
There are three types of overcurrent relay (OCR) used for motor protection: Electronic Thermal Electromagnetic Electronic OCIT (overcurrent inverse time) relays have largely supers... Read more
Protecting an electric motor basically involves preventing the motor from getting too hot. Remember, every 10*C above the maximum recommended temperature of the insulation can redu... Read more
The standard cage-rotor a.c. induction motor operates as an almost constant speed drive over its load range. This feature is satisfactory for most of the ship’s auxiliary ser... Read more
When motor direct-on-line started with the stator winding star connected, it will only take one-third of the starting current that it would take if the windings were delta connecte... Read more
LV generator circuit-breakers and other large distribution circuit-breakers (600-6000 A) on board ship are traditionally of the air break type called ACB (air circuit breaker). Thi... Read more
The central section of the main switchboard is used for the control of the main generators. The switchgear cubicles on either side of the generator panels are used for essential se... Read more
