MJHM

ModelMJHM
PowerUp to 11.000 kVA
VoltagesUp to 15.000 V
Frame400 ÷ 1.250
Poles4, 6, 8, 10 and 12
(over contact MM)
CoolingIC 01
IPIP 23. Available up to IP 44 with filters
EnclosureODP - Open Drip Proof
Main ApplicationsAuxiliary generator, Emergency, Hybrid machine, Off-shore and variable speed generator, Propulsion generator, Shaft generator
SectorMarine
  • Poles | kVA | 60 Hz
  • Certificates and testing
  • Main components
  • Construction
  • Technical data
  • Operating conditions
  • Auxiliary device
  • Optional features

Poles | kVA | 60 Hz

4
4
10.000
6
6
9.000
8
8
11.000
10
10
11.000
12
12
10.000

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.
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 data
Made 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 top.
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.

Construction

Cooling System
Cooling System
IC 01 as per IEC60034-6
Degree of protection
Degree of protection
IP 23 as per IEC60034-5
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 data
Single 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:
  • 4, 6 poles: insulated ND end bearing from 630 frame size
  • 8 poles: insulated bearing from 400 frame size
  • 10 poles: insulated bearing from 500 frame size
All ND end sleeve bearings are insulated as standard. All configurations are designed to withstand the following marine inclination.
Static Dynamic
List 15° Rolling ±22.5°
Trim Pitch ±7.5°
Dedicated constructions available for different values.
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: F class insulated with a synthetic enamel (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.
SizeType
400 - 450 MEC 20 analog/ digital
500 - 560 M40FA610A analog
630 - 710 M63FA310A analog
800 - 1.250 MEC 100 digital
Overboosting device
Overboosting device
SizeType
Medium voltageAllCT + Overboosting device
High voltageAllPMG
Space heaters
Space heaters
Heaters installed at ND end side.
SizePower (W)
400-560400
630 - 710600
800 - 900800
1.0001.000
1.1201.200
1.2501.400
RTD-PT100
RTD-PT100
RTD devices in standard configuration:
  • 1+1 RTD on each phase of stator winding
  • 1 RTD on each bearing
Terminals in auxiliary terminal box.
Other configurations available:
  • DUPLEX type
  • RTD for inlet / outlet air

Optional features

List
List
  • Reinforced construction for high linear vibrations
  • flanged shaft for direct coupling with engine flywheel (in case of single bearing solution)
  • neutral point terminals in separate terminal box
  • increase protection degree up to IP 44 with filters
  • lifted feet to couple the generator with engine on existing baseframe
  • redundant rotating rectifier with 12 diodes
  • insulated bearing and earthing brush
  • AVR supplied loose
  • automatic power factor control (analog type)
  • digital AVR MEC100 for frame 400 – 710 (supplied loose)
  • digital AVR MEC100D with diode failure monitoring
  • redundant AVR system
  • excitation/overboosting PMG mounted on generator
  • lubrication system for sleeve bearing
  • other options available on request.

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