Model B4JH B5JH
Power Up to 4.000 kW
Voltages Up to 6.600 V
Frame 355 ± 630
Poles 4, 6, 8 and 10
Cooling IC 71W
IP IP 55/ 56
Main applications Propulsion, thruster, dredge pump, hybrid machine, PTO-PTI system
Other applications Fi - Fi system
Sector Marine

Poles kW | 60 Hz
4 4.000
6 3.800
8 2.900

Rigid frame, rugged welded steel fabrication (EN 10025 - S235 JR).
Frame is provided with side ribs to increase the strength.
Marelli Motori motors for continuous duty operation are designed to meet vibration levels per IEC 60034-14, ISO 10816-1 and BS 5000-3.

Made of grey cast-iron (EN 1561 – GJL 200) up to 500 frame size motors. Made of hot-rolled structural steel (EN 10025 – S235 JR) from size 560 and above

General data
Made in carbon steel (EN 10083 – 2 C40 – TN) up to 450 frame and hotrolled structural steel from 500 frame (EN 10025 – S355 JR). 
Shaft design
Cylindrical shaft with key

Main terminal box
Mounted on top or side (with vertical mounting) and made in cast iron or cold rolled formable steels depending from size.

Internal Fan
Made of aluminium alloy for 450 and 500 frame size.
Made of hot-rolled structural steel from frame size 560 and above (EN 10025 – S235 JR).

Heat Echanger
General data
Heat exchanger is part of the housing and built on the machine. The material of the frame is carbon steel according to the standard EN 10025-S275JR. Equipped with water leakage detector as standard.
Exchanger data

  • Working pressure < 6 bar
  • Test pressure 9 bar
  • Max glycol : 20%
  • Coolant : fresh water only

TEWC – Totally Enclosed Water Cooled

Cooling System
IC 71W as per IEC60034-6.
7 : Heat exchanger. The primary coolant is circulated in a closed circuit
which is built as integral part of the machine.
1 : Self-circulation. The coolant is moved by a fan mechanically driven by the rotor.
W : Coolant. Cooling water must be clean water.

Degree of protection
IP 55 as per IEC60034-5.

IM B3, V1 and V10 as per IEC60034-7.

Marine Survey Certificate supplied with the machine.
Shaft, housing (propulsion) and exchanger are certified by the Marine Classification Society.
Motors are ABS, RRR and DNV type approved.

Stator/Rotor core

 Laminated and enamel-insulated on both sides to minimise eddy-current losses. The stator winding is made of flat copper or round copper wire depending on the machine size. The completely wound stator pack with housing is thereby impregnated in an epoxy-resin VPI. The subsequent heat treatment hardens the resin.


 Squirrel cage rotor type.
Depending on machine size, the rotor construction is either a solid shaft or welded ribbed shaft.
The rotor winding can be either a pressure die cast aluminum or a copper bar construction.


 General data
Antifriction bearings 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.
Both bearings are fitted with a regreasing system.
The used grease is removed through a valve locked in the outer bearing cover. Sleeve bearings available as an option.
On request special bearings are designed where high radial and axial forces are applied. All configurations are designed to withstand the following marine inclination.

List 15°
Trim 5°


Rolling ±22.5°
Pitch ±7.5°

Dedicated constructions available for different values.

Impregnation system

 Stator and rotor are VPI treated with an unsaturated polyester amide resin which is polymerised in an oven.

Insulation system

Low voltage 
Stator: F class insulated with a synthetic enamel. 
(H class insulation available on request)

Protective treatments
Marine dedicated protective enamel is applied on the winding.

Optional features

  • Dual/multiple winding configuration
  • flanged shaft or special shaft end on both sides
  • increase protection degree up to IP 56
  • encoder
  • vibration sensors
  • special frame design to suite the application
  • special bearings (sleeve or angular contact bearings)
  • reinforced winding for VFD operation
  • insulated bearings design for VFD application
  • shaft earth brush for VFD application
  • other options available on request.