Synchronous electrical machine, and associated propulsion oriented drive device, boat, and method for cooling such a machine

A synchronous electrical machine comprising:

• a machine housing including:
• a stator and a rotor lodged in the stator, the rotor (i) being separated from the stator by an airgap and (ii) made of individual poles obtained with either magnet blocks or wounded coils, the stator comprising stacks of laminations and at least one channel extending along a longitudinal direction of the stator and formed in the laminations, two adjacent stacks of laminations being separated by pins or specific spacers to form an extraction duct connected to the channel;
• and
• an extraction opening so that a fluid being (i) cooled and delivered via a cooling fluid unit and (ii) injected in the air gap at the ends of the stator flows in the extraction duct and in the channel, and is extracted from the machine through the extraction opening to cool the stator and the rotor;
• and
• wherein an entire circumference of the stator is in direct contact with the machine housing, the machine housing surrounding the stator in such a manner that there is no air layer between the stator and the machine housing, thereby allowing an efficient thermal exchange by conduction with a liquid surrounding the housing without compromising the air circulation inside the machine.