IEC 61892-5:2000 pdf download

IEC 61892-5:2000 pdf download.Mobile and fixed offshore units – Electrical installations – Part 5:Mobile units.
3.10
semiconductor convertor
static device using semiconducting elements to convert electric energy from one state to another
3.11
steering gear control system
equipment by which orders are transmitted from the navigating bridge to the steering gear power units
NOTE St..ring gear ontroI systems compris, transmitters, receivers, htraulic control pumps and their associated motors, motor contollers. piping and cables, etc.
3.12
steering gear power unit (electric steering gear
electric motor arid Is associated electrical equipment used to operate the steering gear
3.13
steering gear power unit (electrohydraulic steering gear)
electric motor and its associated electrical equipment and connected pump used to operate the steering gear
4 General requirements
4.1 In every mobile unit in which electric power is used br the services necessary br the safety oP the unit, the generators. switchgear, motors and associated controlgear for such services, with the exception of machinery in the platform of semi-submersibles. shall be so situated or arranged that they continue to operate satisfactorily In the event of partial flooding by bilge water above the tank top In the space in which they are situated. The design criterion for partial flooding shall be assumed to be a depth of water 1I12’ beam but not exceeding a depth of 1,5 m except where this requirement is impracticable for horizontally mounted propulsion generators and motors In such circumstances the machine enclosures shall, at least, be watertight to the underside of the shaft.
4.2 RotatIng machines shall be installed to minimise the effects of motion. The design of bearings of all machines and the arrangement for their lubrication shall be adequate to withstand the motions encountered in heavy weather and operation for prolonged periods at the list and trim specified In clause 5 without the spillage of oil.
4.3 Conductors and equipment shall be placed at such a distance from each magnetic compass or shall be so disposed that tt’ie interfering external magnetic field is negligible; that is, the total singular deviation shall not exceed 30 minutes when any combination of circuits is switched on and off.
4.4 Where the total installed electrical power of the main generators exceeds 3 MW the busbars of the main switchboard shall be subdivided into at least two parts. The subdivision may be effected by removable links, circuit-breakers or other suitable means so that the main generators and any supplies to duplicated services which are directly connected to the busbars are, as far as is practicable, equally divided between the sections.
5 Limits of inclination of the unit
51 Dependent upon the outcome of all studies relevant to the intact and damaged stability of the unit, the appropriate authority may require or permit deviations from the angles stated in 5.2, 5.3 and 5.4.
5.2 All machines and apparatus shall operate satisfactorily under all conditions with the unit
upright and when inclined up to the following angles from the normal:
— for column stabilized units, 150 in any direction;
— for self-elevating units, 10° in any direction;
— for surface units. 150 eIther way In list and simultaneously trimmed 5° by the bow or stern.
5.3 Main propulsion machinery and all auxiliary machinery essential to the propulsion and
safety of the mobile unit shall be capable of operating under the static conditions specified in
5.2 and the following dynamic conditions:
— for column stabilized units, 22° 30’ In any direction:
— for sell-elevating units, 150 in any direction;
— for surface units, 22° 30’ rolling and simultaneously pitching 70 30’ by the bow or stern.
5.4 Emergency machines and apparatus fitted in accordance with requirements from the appropriate authority for emergency plant shall operate satisfactorily under all conditions with the unit upright and when inclined up to the following maximum angles from the normal:
— for column stabilized units, 25° in any direction:
— for self-elevating units, 15° in any direction;
— for surface units, 22° 30’ about the longitudinal axis andlor when inclined 10 about the transverse axis.
5.5 Where required by the appropriate authority, dynamic condition limits shall apply as follows:
— rotation about fore-and-aft axis (rolling). ±22° 30’
— rotation about athwartship (pitching), ±70 30’
NOTE These motions may occur s.inullaneously.
6 Bilge pumps
6.1 Motors of permanently installed emergency bilge pumps, if any, shall be connected to an emergency switchboard
6.2 Cables and their connections to submersible pumps shall be capable of operating under a head of wafer equal to their distance below the worst damaged condition waterline. The cables shall either be armoured or mechanically protected by other means and shall not be installed within the assumed extent of damage. They shall be installed in continuous lengths from above the worst damaged condition waterline to the motor terminals, entering the air-bell from Its underside.
6.3 Under all circumstances it shall be possible to start the motor of a permanently installed bilge pump from a convenient point above the worst damaged condition waterline and in a space not within the assumed extent of damage.
NOTE The worst damaged condition waterlin, and th, spaces wlhin th, assumed .st.nI of damage shall be in accordance wth IMO requirements.