MJRM
| Model | MJRM |
| Power | Up to 6.500 kVA |
| Voltages | Up to 690 V |
| Frame | 250 ± 900 |
| Poles | 4, 6, 8, 10 and 12 (over contact MM) |
| Cooling | IC 81W/ IC 86W |
| IP | IP 44. Available up to IP 56. |
| Enclosure | TEWAC - Totally Enclosed Water to Air Cooled. |
| Main Applications | Auxiliary generator, Hybrid machine, Off-shore and variable speed generator, Propulsion generator, Shaft generator |
| Sector | Marine |
- Poles | kVA | 60 Hz
- Certificates and testing
- Main components
- Construction
- Technical data
- Operating conditions
- Auxiliary device
- Optional features
Poles | kVA | 60 Hz
| 4 |
4
4.000 |
| 6 |
6
5.000 |
| 8 |
8
6.500 |
| 10 |
10
6.000 |
| 12 |
12
5.400 |
Certificates and testing
| Applicable standards |
Applicable standards
Generators are designed in compliance with: IEC EN 60034 - 1 BS 4999 - 5000 VDE 0530 NF 51 - 100 NF 51 - 111 OVE M - 10 NEMA MG 1.32 Generators conform to EU rules. UL/CSA certifications available on request. |
| Certificate |
Certificate
Marine Survey Certificate supplied with the machine. Marelli Motori has the ABS design assessment. Shaft, housing (propulsion) and exchanger are certified by the Marine Classification Society. |
Main components
| Housing |
Housing
Rigid frame, rugged welded steel fabrication (EN 10025 - S235 JR). Frame is provided with side ribs to increase the strength. Marelli Motori generators for continuous duty operation are designed to meet vibration levels per IEC 60034-14, ISO 10816-1 and BS 5000-3. |
| Shield |
Shield
Made of spheroidal graphite cast-iron (EN 1563) or grey cast-iron (EN 1561) up to 630 frame size. Made of structural steel (EN 10025 – S235 JR) above. |
| Shaft |
Shaft
General dataMade in carbon steel and obtained by lamination (EN 10083–2 C40–TN). Shaft is obtained by forging from 290 mm diameter and above. The shaft is tested at the manufacturer in order to check it is defect-free. Shaft design Double bearing generator: cylindrical shaft with key. |
| Main terminal box |
Main terminal box
Mounted on side (right or left will be selected). Made of formable steels EN 10130. |
| Fan |
Fan
Made of aluminum alloy (EN 1706) or structural steel (EN 10025 – S235 JR) depending upon application requirments. |
| Heat Exchanger |
Heat Exchanger
ConstructionMounted on top of alternator. Double tube made of CuNi 90/10. Copper fins housing. Equipped with water leakage detector. Exchanger data
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Construction
| Cooling System |
Cooling System
IC 81W as per IEC60034-6. Primary fluid (water) is flowing by external water system. Internal air is flowing by a fan mounted on the shaft of the generator at the driven side. |
| Degree of protection |
Degree of protection
IP 44 as per IEC60034-5. (Available up to IP 56) |
| Mounting |
Mounting
Horizontal - IM 1001 or IM 1101 as per IEC 60034-7 |
Technical data
| Stator/Rotor core |
Stator/Rotor core
Laminated and enamel-insulated on both sides to minimise eddy-current losses. | ||||||||||||
| Rotor |
Rotor
Salient pole type. Made by copper flat wire. H class insulated with enamel coating. Winding retaining by pass-through bars of high quality steel. Rotating rectifier: Graetz diode bridge with 6 diodes. Rotors are dynamically balanced with a half key applied to the shaft extension in accordance with IEC 60034-14 to vibration grade normal A. Special vibration level construction is available. | ||||||||||||
| Bearing |
Bearing
General dataSingle or double antifriction bearing grease lubricated (ball or roller type) or oil lubricated sleeve bearing. The theoretical lifetime of bearings, L10h according to ISO 281/1 standard, of standard horizontal construction generators, without external forces (radial and / or axial) is in excess of 50.000 hours. On request, the lifetime of bearings, L10h can be in excess of 100.000 hours. Locating bearings are on the D end side and floating bearings on the ND end side. Bearing selection Antifriction bearings up to 560 frame size included. Sleeve bearings from 630 frame size included (available for smaller frame sizes). Antifriction bearings can be mounted on 630/710 frame size according to site working conditions. Regreasing system (for antifriction bearing) Both bearings are fitted with grease nipple. Bearing insulation ND end bearing can be insulated to prevent any harmful circulating current from passing through the bearing surfaces. Insulated antifriction bearings in standard configuration:
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| Impregnation system |
Impregnation system
Stator and rotor are VPI treated with an unsaturated polyester amide resin which is polymerised in an oven. | ||||||||||||
| Insulation system |
Insulation system
Stator: H class insulated with a synthetic enamel (class F standard for generators with H>=800 or form wound form H=400. Class H option with BH technology). Rotor: H class insulated with a synthetic enamel. | ||||||||||||
| Protective treatments |
Protective treatments
Specific marine treatment. Epoxivinilic and polyacrylic. Total minimum thickness 120 micromillimeters. Epoxivinilic: Epoxy two component products, with vinyl change. Polyacrylic: Two components polyurethane product formulated with unmodified hydroxyl acrylic resin. | ||||||||||||
Operating conditions
| Overloads |
Overloads
During continuous duty (S1), the following overloads are allowed: 10% for 1 hour 15% for 10 minutes 30% for 4 minutes 50% for 2 minutes These overloads must be occasional and followed by one hour of running at normal load or less. |
| Parallel operations |
Parallel operations
All generators are provided with an amply sized damper cage and are suitable for parallel operations with other generators, when equipped with the paralleling unit. A power factor regulator (to work in parallel with the main) is available on request. |
| Transient ratings |
Transient ratings
All generators comply with marine rules regarding transient performance. The voltage drop due to the application of 60% of nominal load is within 15%. |
| Three pahse short circuit current |
Three pahse short circuit current
All generators equipped with an overboosting device ensure a three phase short circuit current (Icc) higher than three times the rated current (In): Icc > 300% In |
| Radio interference |
Radio interference
All generators are equipped with Class B Group 1 radio interference filters as defined by EN 55011. |
| THD (Total Harmonic Distortion) |
THD (Total Harmonic Distortion)
The no-load voltage wave form is sinusoidal with THD content less than 2%. |
| Vibrations |
Vibrations
Vibration level is in accordance with ISO 10816. Measurement, evaluation and limits of vibration severity are in accordance with IEC 60034-14. |
Auxiliary device
| AVR |
AVR
Automatic voltage regulator mounted on board.
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| Overboosting device |
Overboosting device
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| Space heaters |
Space heaters
Heaters installed at ND end side.
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| RTD-PT100 |
RTD-PT100
RTD devices in standard configuration:
Other configurations available:
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Optional features
| List |
List
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