MJV
Model MJV
Power Up to 4.550 kVA
Voltages Up to 690 V
Frame 250 ± 900
Poles 4, 6, 8, 10 and 12 (over contact MM)
Cooling IC 611
IP IP 55. Available up to IP 56.
Enclosure TEAAC – Totally Enclosed Air to Air Cooled
Main Applications Auxiliary generators, Emergency, Power generation
Sector Oil&Gas
Poles | Header |
---|---|
4 | 3.500 |
6 | 4.550 |
8 | 4.550 |
10 | 4.550 |
12 | 4.000 |
Certificates and testing
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.
Adherence to ISO 8528 group G preformance classes.
Main components
Housing
Rigid frame, rugged welded steel fabrication (EN 10025 - S235 JR).
Frame is provided with side ribs to increase the strength.
Marelli Generators for continuous duty operation are designed to meet vibration levels per IEC 60034-14, ISO 10816-1 and BS 5000-3.
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
General data
Made in carbon steel and obtained by lamination (EN 10083 – 2 C40 – N).
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
Mounted on side (right or left will be selected).
Made of formable steels EN 10130.
Fan
Made of aluminum alloy (EN 1706) or structural steel (EN 10025–S235 JR) depending on application requirements.
Internal Fan
Made of structural steel (EN 10025 - 5235 JR)
Heat Exchanger
Construction
- Mounted on top of alternator
- Tube made of P - AIMgSi UNI 3569
- Housing: EN 10025 - 5235JR
Construction
Cooling System
IC 611 as per IEC60034-6. Primary fluid (air) driven by a second fan (internal fan) mounted on shaft at ND end side. Internal air is flowing by a fan mounted on the shaft of the generator at the driven side.
Operating temperature
Up to 60° C ambient temperature (over contact Marelli Motori)
Degree of protection
IP 55 as per IEC60034-5. Other protection degree available on request.
Mounting
Horizontal - IM 1001 or IM 1101 as per IEC 60034-7. Other mounting available on request.
Technical data
Stator/Rotor core
Laminated and enamel-insulated on both sides to minimise eddy-current losses
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 are available.
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 800 frame size included. Sleeve bearings from 900 frame size included (available for smaller frame sizes).
Regreasing system:
Up to 250 frame size:
- D-end bearing is prelubricated with inner bearing cap and without grease nipple
- ND-end bearing is with shield (2Z) without regreasing system
315 - 355 frame size:
- D-end bearing is fitted with inner bearing cap and with gerase nipple
- ND-end bearing is with shield (2Z) without regreasing system
400 frame size:
- D-end bearing is fitted with inner bearing cap and with gerase nipple
- ND-end bearing is prelubricated with inner bearing cap and without grease nipple
450 frame size and above: 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.
Impregnation system
Stator and rotor are VPI treated with an unsaturated polyester amide resin which is polymerised in an oven.
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
Specific Oil&gas 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
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
All generators are provided with a 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 performance
All generators can be designed to meet specific reactance values (x'd and x''d). Values can be confirmed by contacting Marelli Motori.
Three pahse short circuit current
All generators equipped with overboosting device ensure a three phase short circuit current (Icc) higher than three times the rated current (In): Icc > 300% In
Radio interference
All generators are equipped with Class B Group 1 radio interference filters as defined by EN 55011.
THD (Total Harmonic Distortion)
The no-load voltage wave form is sinusoidal with THD content less than 2%.
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
Automatic voltage regulator mounted on board.
Size
Type
250
MARK V analog
315 - 450
MEC 20 analog/ digital
500 - 560
M40FA610A analog
630 - 710
M63FA310A analog
800 - 900
M63FA310A analog
Digital AVR available for all sizes on request.
Overboosting device
Low voltage
Size
Type
Low voltage
250 - 450 (4 poles)
Auxiliary winding
400 - 450 (>4 poles)
Varicomp
500 - 710 (all polarities)
Varicomp
800 - 900
PMG
PMG available for all sizes on request.
Space heaters
Heaters installed at ND-end side.
Size
Power(W)
400 - 560
400
630 - 710
600
800 - 900
800
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
- RTD into oil tank for sleeve bearing
Optional features
- Flanged shaft for direct coupling with engine flywheel (in case of single bearing solution)
- neutral point terminals in separate terminal box
- dedicated current transformer installed on neutral point (differential protection and measurement)
- cooling system IC 616 with additional forced ventilation
- increase protection degree up to IP 56 with filters
- dedicated lubrication unit for sleeve bearing solution
- 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 or included into digital regulation)
- digital AVR MEC100 for frame 250 – 710 (supplied loose)
- digital AVR MEC100D with diode failure monitoring
- other digital AVR available on request
- redundant AVR system
- excitation/overboosting PMG mounted on generator
- arrangement for earthing rotor fault protection 64R
- other options available on request.