Section 9 Rotating machines

9.1.1 In addition to the requirements of this Section, rotating machines are to comply with the relevant requirements of the following standards, amended where necessary for ambient temperature, see Pt 16, Ch 2, 1.9 Ambient reference and operating conditions:

1. IEC 60034 Rotating electrical machines (all parts); and
2. IEC 60092 Electrical installations in ships (all parts); or
3. an alternative International or National Standard acceptable to LR.

9.1.2 The insulation systems of electrical rotating machines used for essential services are to be tested following the principles detailed in IEC 60505, Evaluation and qualification of electrical insulations systems, or an equivalent National Standard acceptable to LR.

9.1.3 For all the rotating machines a manufacturer's test certificate is to be provided, see also Pt 16, Ch 2, 1.4 Surveys.

9.1.4 All machines of 100 kW and over, intended for essential services, are to be surveyed by the Surveyor during manufacture and test, see also Pt 16, Ch 2, 1.4 Surveys 1.4.5.

9.1.5 Shaft materials for rotating machines for essential services are to comply with the Rules for the Manufacture, Testing and Certification of Materials, July 2022 and be manufactured under LR survey for the following applications:

1. shaft material for dynamic positioning and electric propulsion motors;

2. shaft material for main engine driven generators where the shaft is part of the propulsion shafting; and

3. shaft material for machines with power ratings of 250 kW or greater.

Shaft material for machines with power ratings less than 250 kW is to have a manufacturer’s certificate as detailed in Ch 1 General Requirements of the Rules for the Manufacture, Testing and Certification of Materials, July 2022.

9.1.6 Where welding is applied to shafts of machines for securing arms or spiders, stress relieving is to be carried out after welding. The finalized assembly is to be visually examined by the Surveyors, crack detection carried out by an appropriate method and the finished welds found sound and free from cracks.

9.1.7 The rotating parts of machines are to be so balanced that when running at any speed in the normal working range the vibration does not exceed the levels of IEC 60034-14: Rotating electrical machines – Part 14: Mechanical vibration of certain machines with shaft heights 56 mm and higher – Measurement, evaluation and limits of vibration severity.

9.1.8 The lubrication arrangement for bearings are to be effective under all operating conditions including the maximum craft inclinations defined by Pt 16, Ch 2, 1.10 Inclination of craft and there are to be effective means provided to ensure that lubricant does not reach the machine windings or other conductors and insulators.

9.1.9 Means are to be taken to prevent the ill effects of the flow of currents circulating between the shaft and machine bearings or bearings of connected machinery.

9.1.10 Alternating current machines are to be constructed such that, under any operating conditions, they are capable of withstanding the effects of a sudden short-circuit at their terminals without damage.

9.1.11 For high voltage rotating machines used for essential services are to comply with the relevant requirements of Pt 6, Ch 2, 1 General requirements and Pt 6, Ch 2, 9 Rotating machines of the Rules and Regulations for the Classification of Ships, July 2022.

9.1.12  The entity responsible for assembling the alternating current generating set is to install a rating plate marked with at least the following information:

1. the generating set manufacturer’s name or mark;
2. the set serial number;
3. the set date of manufacture (month/year);
4. the rated power (both in kW and kVA) with one of the power rating prefixes COP, PRP (or, only for emergency generating sets, LTP) as defined in ISO 8528-1 Reciprocating internal combustion engine driven alternating current generating sets;
5. the rated power factor;
6. the set rated frequency (Hz);
7. the set rated voltage (V);
8. the set rated current (A); and
9. the mass (kg).

9.2.1 Generators, including their excitation systems, and continuously rated motors are to be suitable for continuous duty at their full rated output at maximum cooling air or water temperature for an unlimited period, without the limits of temperature rise in Pt 16, Ch 2, 9.3 Temperature rise being exceeded. Generators are to be capable of an overload power of not less than 10 per cent at their rated power factor for a period of 15 minutes without injurious heating. Other machines are to be rated in accordance with the duty which they have to perform and, when tested under rated load conditions, the temperature rise is not to exceed the values in Pt 16, Ch 2, 9.3 Temperature rise.

9.2.2 When a rotating machine is connected to a supply system with harmonic distortion the rating of the machine is to allow for the increased heating effect of the harmonic loading.

9.2.3 The design and construction of smoke extraction fan motors are to be suitable for the ambient temperature and operating time required. Type test reports to verify the performance of the electric motor are to be submitted for consideration.

9.3.1 The limits of temperature rise specified in Table 2.9.1 Limits of temperature rise of machines cooled by air, are based on the cooling air temperature and cooling water temperature given in Pt 16, Ch 2, 1.9 Ambient reference and operating conditions.

9.3.2 If it is known that the temperature of cooling medium exceeds the values given in Pt 16, Ch 2, 1.9 Ambient reference and operating conditions the permissible temperature rise is to be reduced by an amount equal to the excess temperature of the cooling medium.

9.3.3 If it is known that the temperature of cooling medium will be permanently less than the values given in Pt 16, Ch 2, 1.9 Ambient reference and operating conditions the permissible temperature rise may be increased by an amount equal to the difference between the declared temperature and that given in Pt 16, Ch 2, 1.9 Ambient reference and operating conditions up to a maximum of 15°C.

9.4.1 Each alternating current generator, unless of the self-regulating type, is to be provided with automatic means of voltage regulation; voltage build-up is not to require an external source of power. Provision is to be made to safeguard the distribution system should there be a failure of the voltage regulating system resulting in a high voltage.

9.4.2 The voltage regulation of any alternating current generator with its regulating equipment is to be such that at all loads, from zero to full load at rated power factor, the rated voltage is maintained within ±2,5 per cent under steady conditions. There is to be provision at the voltage regulator to adjust the generator no load voltage.

9.4.3 Generators, and their excitation systems, when operating at rated speed and voltage on no-load are to be capable of absorbing the suddenly switched, balanced, current demand of the largest motor or load at a power factor not greater than 0,4 with a transient voltage dip which does not exceed 15 per cent of rated voltage. The voltage is to recover to rated voltage within a time not exceeding 1,5 seconds.

9.4.4 The transient voltage rise at the terminals of a generator is not to exceed 20 per cent of rated voltage when rated kVA at a power factor not greater than 0,8 is thrown off.

9.4.5 Generators and their voltage regulation systems are to be capable of maintaining, without damage, under steady state short circuit conditions a current of at least three times the full load rated current for a duration of at least two seconds or where precise data is available for the duration of any time delay which may be provided by a tripping device for discrimination purposes.

9.4.6 Generators required to run in parallel are to be stable from no load (kW) up to the total combined full load (kW) of the group, and load sharing is to be such that the load on any generator does not normally differ from its proportionate share of the total load by more than 15 per cent of the rated output (kW) of the largest machine or 25 per cent of the rated output (kW) of the individual machine, whichever is less.

9.4.7 When generators are operated in parallel, the kVA loads of the individual generating sets are not to differ from the proportionate share of the total kVA load by more than 5 per cent of the rated kVA output of the largest machines.

9.5.1 Machines are to withstand on test, without injury, the following occasional overloads.

1. Generators. An excess current of 50 per cent for 30 seconds after attaining the temperature rise corresponding to rated current, the terminal voltage being maintained as near the rated value as possible. The forgoing does not apply to the overload torque capacity of the prime mover.

2. Motors. At rated speed or, in the case of a range of speeds, at the highest and lowest speeds, under gradual increase of torque, the appropriate excess torque given below. Synchronous motors and synchronous induction motors are required to withstand the excess torque without falling out of synchronism and without adjustment of the excitation circuit preset at the value corresponding to rated load:

   d.c. motors	50 per cent for 15 seconds;
   polyphase a.c. synchronous motors	50 per cent for 15 seconds;
   polyphase a.c. synchronous induction motors	35 per cent for 15 seconds;
   polyphase a.c. induction motors	60 per cent for 15 seconds.

9.6.1 Where water cooled heat exchangers are used in the machine cooling circuit there is to be provision for the detection of water leakage and the system is to be arranged so as to prevent the entry of water into the machine.

9.6.2 An alarm is to be provided to indicate high cooling water temperature.

9.7.1 The final running position of brushgear is to be clearly and permanently marked.

9.7.2 Direct current machines are to work with fixed brush setting from no load to the momentary overload specified without injurious sparking.

9.8.1 On machines for essential services tests are to be carried out and a certificate furnished by the manufacturer. The tests are to include temperature rise, momentary overload, high voltage, and commutation. The insulation resistance and the temperature at which it was measured are to be recorded.

9.8.2 In the case of duplicate machines, type tests of temperature rise, excess current and torque and commutation taken on a machine identical in rating and in all other essential details may be accepted in conjunction with abbreviated tests on each machine. Type tests for propulsion machines will be specially considered. For the abbreviated tests, each machine is to be run and is to be found electrically and mechanically sound and is to have a high voltage test and insulation resistance recorded.

9.8.3 A high voltage test, in accordance with Pt 16, Ch 2, 21 Testing and trials, is to be applied to new machines, preferably at the conclusion of the temperature rise test. Where both ends of each phase are brought out to accessible separate terminals each phase is to be tested separately.

9.8.4 An impulse test is to be carried out on the coils of high voltage machines in accordance with IEC 60034-15: Rotating electrical machines – Part 15: Impulse voltage withstand levels of form-wound stator coils for rotating a.c. machines, in order to demonstrate a satisfactory withstand level of the inter-turn insulation to voltage surges. The test is to be carried out on all coils after they have been inserted in the slots and after wedging and bracing. Each coil shall be subjected to at least five impulses of injected voltage, the peak value of the injected voltage being given by the formula:

Alternative proposals to demonstrate the withstand level of inter-turn insulation will be considered.