Lloyds Register Rulefinder 2009 Version 9.12

Rulefinder Version 9.12 (July 2009) - Lloyds Register Rules and Regulations - Rules and Regulations for the Classification of Ships, July 2009 - Control, Electrical, Refrigeration and Fire - Electrical Engineering - Testing and trials

Section 20 Testing and trials 20.1 Testing 20.1.1. Tests in accordance with 20.1.2 to 20.1.4 are to be satisfactorily carried out on all electrical equipment, complete or in sections, at the manufacturers premises and a test report issued by the manufacturer.

20.1.2. A high voltage at any frequency between 25 and 100Hz is to be applied between:

(a). all current carrying parts connected together and earth;

(b). all current carrying parts of opposite polarity or phase.

For rotating machines the value of test voltage is to be 1000 V plus 2 x rated voltage with a minimum of 2000 V, and for other electrical equipment, it is to be in accordance with Table 2.20.1. Items of equipment included in the assembly for which a test voltage lower than the above is specified may be disconnected during the test and tested separately at the appropriate lower test voltage. The test is to be commenced at a voltage of about one-third the test voltage and is to be increased to full value as rapidly as is consistent with its value being indicated by the measuring instrument. The full test voltage is then to be maintained for 1 minute, and then reduced to one-third full value before switching off. The assembly is considered to have passed the test if no disruptive discharge occurs.

20.1.3. When it is desired to make additional high voltage tests on equipment which has already passed its tests, the voltage of such additional tests is to be 80 per cent of the test voltage the equipment has already passed.

Table 2.20.1 Test voltage

20.1.4. Immediately after the high voltage test, the insulation resistance is to be measured using a direct current insulation tester, between:

(a). all current carrying parts connected together and earth;

(b). all current carrying parts of different polarity or phase.

The minimum values of test voltage and insulation resistance are given in Table 2.20.2.

Table 2.20.2 Test voltage and minimum insulation

20.1.5. Tests in accordance with the Standard with which the equipment complies may be accepted as an alternative to the above.

Rated voltage, Un

Un V Test voltage a.c. (r.m.s.), V

Un = 60 500

60 < Un = 1000 2 x Un + 1000

1000 < Un = 2500 6500

2500 < Un = 3500 10000

3500 < Un = 7200 20000

7200 < Un = 12000 28000

12000 < Un = 15000 38000

Rated voltage Un V

Minimum voltage of the tests, V Minimum insulation resistance, M

Un = 250 2 x Un 1

250 < Un = 1000 500 1

1000 < Un = 7200 1000

7200 < Un = 15000 5000

20.2 Trials 20.2.1. Before a new installation, or any alteration or addition to an existing installation, is put into service the applicable trials in 20.2.2 to 20.2.7 are to be carried out. These trials are in addition to any acceptance tests which may have been carried out at the manufacturers works and are to be to the Surveyors satisfaction.

20.2.2. The insulation resistance is to be measured of all circuits and electrical equipment, using a direct current insulation tester, between:

(a). all current carrying parts connected together and earth and, so far as is reasonably practicable;

(b). all current carrying parts of different polarity or phase;

The minimum values of test voltage and insulation resistance are given in Table 2.20.2. The installation may be subdivided and appliances may be disconnected if initial tests produce results less than these figures.

20.2.3. Tests are to be made to verify the effectiveness of:

(a). earth continuity conductor;

(b). the earthing of non-current carrying exposed metal parts of electrical equipment and cables not exempted by 1.11.2;

(c). bonding for the control of static electricity.

20.2.4. It is to be demonstrated that the Rules have been complied with in respect of:

(a). satisfactory performance of each generator throughout a run at full rated load;

(b). temperature of joint, connections, circuit-breakers and fuses;

(c). the operation of engine governors, synchronising devices, overspeed trips, reverse-current, reverse-power and over-current trips and other safety devices;

(d). voltage regulation of every generator when full rated load is suddenly thrown off and when starting the largest motor connected to the system;

(e). satisfactory parallel operation, and kW and KVA load sharing of all generators capable of being operated in parallel at all loads up to normal working load;

(f). all essential and other important equipment are to be operated under service conditions, though not necessarily at full load or simultaneously, for a sufficient length of time to demonstrate that they are satisfactory;

(g). propulsion equipment is to be tested under working conditions and operated in the presence of the Surveyors and to their satisfaction. The equipment is to have sufficient power for going astern to secure proper control of the ship in all normal circumstances. In passenger ships the ability of the machinery to reverse the direction of thrust of the propeller in sufficient time, under normal manoeuvring conditions, and so bring the ship to rest from maximum ahead service speed, is to be demonstrated at the sea trial.

20.2.5. Voltage drop is to be measured, where necessary, to verify that this is not in excess of that specified in 1.7.

20.2.6. It is to be demonstrated by practical tests that the Rules have been complied with in respect of fire, crew and passenger emergency and ship safety systems.

20.2.7. On completion of the general emergency alarm system and the public address system tests, the Surveyor is to be provided with two copies of the test schedule, detailing the measured sound pressure levels. Such schedules are to be signed by the Surveyor and the Builder.

20.3 High voltage cables 20.3.1. Before a new high voltage cable installation, or an addition to an existing installation, is put into service a voltage withstand test is to be satisfactorily carried out on each completed cable and its accessories. The test is to be carried out after the insulation resistance test required by 20.2.2 and may use either an a.c. voltage at power frequency or a d.c. voltage.

20.3.2. When an a.c. voltage withstand test is carried out, the voltage is to be not less than the normal operating voltage of the cable and it is to be maintained for a minimum of 24 hours.

20.3.3. When a d.c. voltage withstand test is carried out, the voltage is to be not less than:

(a). 1,6 (2,5Uo + 2 kV) for cables of rated voltages (Uo) up to and including 3,6 kV, or