For two years, ALXION has devoted Research and Development activities to the design and experimentation of roto-stator kits for STK motors whose air gap is immersed in a heat transfer fluid in liquid or gaseous phase for heat pump applications.for the conversion of geothermal energy or thermal effluents into electrical energy.The new rotor and the new stator are special and allow both the protection of the permanent magnets, the magnetic circuit and the windings against the aggression of the fluid by sealing the air gap with stainless steel on the stator and the rotor.The original technology developed with low thermal resistance can allow losses from the motor itself to be evacuated by the heat transfer fluid without the addition of an external cooling circuit.Since January 2020, the series applications have been in operation on site.