The main elements of a marine distribution system are the main and emergency switchboards, power panel boards, motor controllers, lighting and small power panel boards. The system is generally designed such that under all normal conditions of operation, power is distributed from the main switchboard. The distribution system is designed to keep cable costs to a minimum by distributing to power panels located close to the user services.
The main switchboard is generally located near the centre of the distribution system and this is normally the main engine room or machinery control room. These locations are normally below the ship's waterline or below the uppermost continuous deck of the ship i.e. the bulkhead or main deck. Consequently, in the event of a fire or flooding it is likely that the main generators and switchboard would be disabled. To ensure that electrical supplies are available to emergency and safety systems, an emergency generator and associated emergency switchboard will be located above the main deck in a separate space, completely isolated from the main machinery spaces.
For shipboard installations specific protective systems are required to shut down all ventilation systems and all fuel oil systems in the event of fire. When motor auxiliaries are grouped together and supplied from a motor control center or a grouped distribution panel, this can best be achieved by providing the MCC supply feeder circuit breaker with an undervoltage tripping device and connecting this to the ventilation or fuel systems trip unit. When grouped MCC's or grouped distribution panels are not used, separate cables must be installed for each motor controller. This leads to increased cable costs and increases the systems process to failure.
Give adequate Russian equivalents of the italicized words. | Read and translate the text. | Визначте форму герундія і переведіть пропозиції на російську мову. | FIRST AID FOR ELECTRIC SHOCK. | Визначте правильне закінчення речень. | Give adequate Russian equivalents of the italicized words. | Read and translate the text. | Герундій у функції підмета. | Переведіть пропозиції, в яких герундий грає роль змістовної частини присудка. | Lesson 5. |