Abstract: An electric motor provided with a bearing of improved design has a stator (1) supported by a mounting frame (3) and a rotor (4) in rigidly fixed relation to a shaft (5), the shaft being rotatably mounted in a plain bearing (7) placed within a tubular support (8) which is rigidly fixed to the motor frame (3). A sleeve (23) composed of material having a sufficient degree of elastic deformability to absorb vibrations is interposed between the outer face (24) of the bearing (7) and the inner face of the tubular support (8). The electric motor is intended in particular to equip propeller-type fans and is primarily applicable to direct-current motors of the electronic commutation type.

Abstract: A centrifugal fan driven by an electronic-commutation d.c. motor is provided with a housing (1) which defines a volute (2), an impeller (4) which is coupled for rotation with the motor shaft (7) being mounted within the fan housing. The motor is placed within a protective casing (13) which also contains at least one printed-circuit board (23) for supporting the motor control circuit (26), the casing being adjacent to the external face (36) of a closure disk (9) of the fan housing (1).The fan motor casing (13) has an annular extension (14) corresponding to the fan housing (1) and the printed-circuit board (23) is housed within said extension and placed in substantially parallel relation to the fan-housing closure disk (9) in sufficiently close proximity to said disk to be subjected primarily by thermal conduction to the cooling action produced by the fan impeller (4).

Abstract: A device providing protection against over-currents in the windings of an electric motor having a rotor (3) and at least two windings (1, 2) comprises at least two parallel thermistors (17, 18) each mounted in series with at least one motor winding (1, 2).

Abstract: A direct-current motor in which a rotor is provided with at least two regions having opposite permanent magnetic polarities and located opposite to an annular air-gap. The stator is constituted by at least one winding and one magnetic circuit comprising at least one yoke connected by means of arms surrounded in one case by the winding to at least two pole horns located opposite to the air-gap. At least one auxiliary permanent magnet is engaged within a space formed between two circumferential ends of the two pole horns, the ends being directed towards each other. The permanent magnet forms a longitudinal projection carried by a supporting post housed within an inter-pole space between the yoke and the two adjacent horns. The post is carried by an annular plate which is placed on an axial end face of the magnetic circuit.

Abstract: The direct-current motor comprises at least one field winding supplied intermittently with direct-current voltage in order to produce a driving torque by interaction with permanent-magnetic poles which rotate with respect to the winding. The electromotive force of induction produced in the winding by the relative rotation of the permanent-magnetic poles is detected by means of a voltage measurement during the time intervals which elapse when the winding is not energized. A low-speed signal is produced when the electromotive force is below a pre-established threshold in correlation with the desired speed-threshold value.

Abstract: A flat type fan is provided having an axial dimension very much less than its radial dimension, comprising a casing forming a cylindrical duct for a fan blade unit.Two webs carry bosses having fixing bores therethrough. The length of the bosses is equal to the length of the casing, which allows the fan to be fixed on a wall by any one of its faces, for blowing or for suction.

Abstract: The part comprises a hole surrounded by a boss having an end surface perpendicular to its side surface. The nut comprises a threaded screwing cap connected to the base of a coupling mounting having also two legs between which the boss is to be inserted. Near its end surface, the boss is provided with projections, each of which is inserted between one of the legs and the cap.

Abstract: The cross-sectional area of the airflow duct on at least one face of the fan housing is larger than the cross-sectional area of a cylindrical portion of duct which cooperates with the impeller. A junction portion having an S-shaped cross-section in an axial plane is provided on at least part of the duct periphery between the cylindrical portion and that housing face. The fan duct progressively increases in width from the cylindrical portion to the housing face and the S-shaped junction portion has a point of inflection substantially at the midpoint of its axial length. A reduction in noise level is thus achieved during operation of the fan.

Abstract: The electric motor with radial air gap comprises a rotor, a stator having a magnetic circuit and windings which form winding heads projecting with respect to the magnetic circuit at the axial ends thereof, a case whose end wall extends radially and a sensor for detecting the position of the rotor fixed on an electrically insulating disc separating that end wall from the winding heads situated on the same side as this wall, applied and immobilized against the case. The sensor has terminals connected to connecting wires which issue from the case at a point remote from the connection point thereof with the terminals, and the internal face of the disc has guide means for leading the wires from one point to the other while passing at a distance from the rotor and the winding heads, which come very close to the end wall.

Abstract: The fan rotor has an axial passage for a stationary shaft, one end of which is secured to the housing. The other end is covered by a plug for sealing-off the axial passage near the impeller hub. An external cover-plate of heat-conducting material is placed over the plug and applied in good thermal contact with the annular end portion of the rotor which is associated with the impeller.

Abstract: A power supply connector placed within a flat fan housing is mounted externally on a cylindrical shell which forms an axial duct for the fan impeller, the impeller being driven by an electric motor which is attached to the shell by means of radial arms. At least one anchoring block placed within a cavity of the connector is provided with retaining means for an internal portion of each connector terminal which is connected to the motor by means of a conductor placed within a channel of the radial arms. The connector terminal has a projecting external portion which can be connected to a power supply. In the service position, the cavity is closed by a cover-plate which maintains the anchoring block and the end portion of each associated conductor, two complementary portions of the anchoring block being interassembled so as to form a housing for retaining the other portion.