Abstract: The invention relates to a centrifugal fan impeller (1) having an axis of rotation (6) and comprising one or more modules (2). Each module (2) comprises a mounting disc (4), at least one connecting ring (5) and a plurality of blades (3) extending between the mounting disc (4) and the connecting ring (5). The blades (3) are connected to the disc (4) and ring (5) at an angle (?) relative to the axis (6) of the impeller (1). The angle (?) at which the blades (3) are inclined may range from 5 to 30 degrees and the blades (3) may be rectangular or trapezoidal in shape depending on the type of performance required: improved capacity with rectangular blades or improved pressure head and acoustic properties with trapezoidal blades. Top performance is thus combined with acoustic comfort.

Abstract: The invention relates to a centrifugal fan impeller (1) having an axis of rotation (6) and comprising one or more modules (2). Each module (2) comprises a mounting disc (4), at least one connecting ring (5) and a plurality of blades (3) extending between the mounting disc (4) and the connecting ring (5). The blades (3) are connected to the disc (4) and ring (5) at an angle (?) relative to the axis (6) of the impeller (1). The angle (?) at which the blades (3) are inclined may range from 5 to 30 degrees and the blades (3) may be rectangular or trapezoidal in shape depending on the type of performance required: improved capacity with rectangular blades or improved pressure head and acoustic properties with trapezoidal blades. Top performance is thus combined with acoustic comfort.

Abstract: The ventilation unit has an electric motor, the output shaft of which is fitted with a fan having a cup-shaped central body and a number of blades. The central body is defined by a base wall, and by an annular wall from whose outer face the blades extend. And the main characteristic of the present invention lies in through windows being formed in the annular wall of the central body to channel out, in use, any condensate formed inside the central body.

Abstract: Method and device (4) for balancing rotors (1), in particular for electric motors, by the addition of material, in which the actual balancing step is carried out by inserting, inside one or more recesses (2) formed in the rotor (1) and designed to seat the rotor winding (3), one or more self-locking balancing devices (4) made of non-ferromagnetic material and having a mass which can be determined beforehand in terms of both its amount and its distribution.

Abstract: The axial flow fan (1) comprises a central hub (3), a plurality of blades (4), each blade (4) having a root (5) and an end (6) and being delimited also by a convex edge (7), whose projection onto the plane of rotation of the fan is defined by a parabolic segment, and by a concave edge (8) whose projection onto the plane of rotation of the fan is defined by circular arc. The blades (4) consist of sections having aerodynamic profiles (18) with a face (18a) comprising at least one initial straight-line segment (t) and a blade angle (&bgr;) that decreases gradually and constantly from the root (5) towards the end (6) of the blade (4) according to a cubic law of variation as a function of the fan radius.

Abstract: The axial flow fan (1; 30) comprises a central hub (3; 33) a plurality of blades (4; 34) which have a root (5; 35), and an end (6; 36). According to one embodiment, the blades (4; 34) are spaced at unequal angles (&thgr;i . . . , n) which can vary in percentage (&thgr;%) from 0.5% to 10%, compared to the configuration with equal spacing angles (&thgr;=) for fans with an equal number of blades. Preferably, the blades (4; 34) are delimited by a convex edge (7; 37), whose projection onto the rotation plane of the fan is defined by a parabolic segment and a concave edge (8; 38) whose projection onto the rotation plane of the fan is defined by a circular arc.

Abstract: A combined support and end cover for electric motors, and for small permanent magnet dc units in particular, which is molded in one piece from insulating plastic material and formed essentially as a flat disk of which the inner surface affords a central socket serving to support the corresponding end of the rotor shaft, a set of slotted holders for the brush contacts, and a number of posts projecting perpendicularly from the periphery of the disk between which the permanent magnet pole pieces are supported.

Abstract: A transmission unit comprises a flexible element (1) in the form of a flexible metal wire (6) on which a plurality of small equidistant coaxial cylindrical bodies (8) are fixed; the element (1) passes endlessly about two opposing drive and driven sprocket wheels (2), (3) respectively, and the two outward and return portions of said element (1) are slidingly received in two flexible sheaths (10); the two sprocket wheels (2), (3) are rotatably mounted in respective casings (4), (5) in which the opposing ends of said two flexible sheaths (10) are clamped.