Abstract: There is disclosed an apparatus for remote opening of doors or gates of at least a building (A, A1 . . . An). The apparatus comprises a unit (B, B 1 . . . Bn) located in the building (A, A1 . . . An) and accessible from a plurality of external terminals (C1 . . . Cn) provided with a GSM module; the unit (B, B1 . . . Bn) is connected to electromechanical means (50) suitable for opening and closing said doors or gates and comprises a database (2) containing the list of the telephone numbers of said plurality of external terminals (C1 . . . Cn), a GSM interface (3) for connecting to the external terminals (C1 . . . Cn) and means (4) for managing said interface (3) and said database (2). The managing means (4) is interrogatable by the external terminals (C1 . . . Cn) and is suitable for commanding the electromechanical means (50) for opening gates or doors if the telephone number of the interrogating external terminal is on the list of telephone numbers of the external terminals (C1 . . . Cn) of the database.

Abstract: An electric fan comprises a blade impeller and an electric motor with a rotor part including a plurality of permanent magnets fixed to a peripheral ring of the impeller, and a stator part which faces a portion of the said ring of magnets of the rotor and which comprises a winding and a support structure in which the impeller is rotatably mounted and to which the stator part of the motor is fixed.

Abstract: A motor-driven fan includes an electric motor including a rotor and a stator in which the rotor includes an essentially cup-shaped cap which extends at least partly around the stator and has a plurality of lateral exit openings adjacent the bottom wall, and an impeller or fan including a hollow hub from which extends a plurality of main outer fan blades. This hub has a front wall fixed to the back wall of the cap of the rotor and a lateral skirt which surrounds the lateral wall of the cap in a radially spaced relationship. The hub is further provided with inner ventilation blades acting in operation to generate a cooling air stream which passes through the motor.

Abstract: A piloting circuit comprises a circuit branch which is intended to be connected to a DC voltage supply source in such a way as to receive a voltage of predetermined polarity, and in which the drain-source path of a (first) MOSFET transistor intended to receive an on-off piloting signal on its gate is connected in series with the load, a current recirculation diode connected in parallel to the load, and protection devices operable to prevent damage to the MOSFET transistor and/or the diode in the event of polarity reversal of the supply voltage. The protection function is achieved of an electronic switch disposed in series with the recirculation diode and piloted in such a way as to prevent the passage of current in this diode if a supply voltage of reversed polarity with respect to the predetermined polarity is applied to the said circuit branch.

Abstract: The fan comprises a hub, the axis of which coincides with the axis of rotation of the fan, and a plurality of blades which extend from the hub between a minimum radial distance from the axis in the vicinity of the hub and a maximum radial distance. In the vicinity of the hub, the cross-section of each blade has an angle of attack and an angle of curvature which are substantially equal to 0° and, starting from the hub, the cross-sections of each blade have angles of attack and angles of curvature which increase as the radial distance from the axis increases, up to a radial distance of between 30% and 40% of the radial extent of the blade.

Abstract: The system comprises a pressure sensor for providing a signal indicative of the pressure of the refrigerant fluid of the air-conditioning system at the output or delivery of the compressor of the system, a sensor for detecting the temperature of the liquid flowing through the engine-cooling system (R), an activation sensor for providing a signal when the air-conditioning system is activated, a sensor for detecting the speed of forward movement of the motor vehicle, and a control and operating unit connected to the sensors and to the electric motor and arranged for: determining a first speed for the electric motor in accordance with a function of the pressure of the refrigerant fluid of the air-conditioning system and of the speed of the vehicle, determining a second speed for the electric motor in accordance with a function of the temperature of the engine-coolant liquid and of the speed of forward movement of the vehicle, and sending to the electric motor control signals to bring its speed of rotation to

Abstract: A circuit comprises at least one electronic switch which is operatively connected to an inductive load, is intended to be driven by means of an on-off signal and, in an enabled condition, can connect the load to a direct-current voltage supply, at least one freewheeling circuit branch which comprises a diode and can recirculate the transient current which flows through the load each time the switch is disabled, and a filtering circuit connected between the diode and the voltage supply and comprising a parallel capacitor connected to the diode and a series inductor connected between the diode and the voltage supply. The freewheeling circuit branch and the filtering circuit are connected substantially in series with one another in a circuit branch which is operatively connected in parallel with the load.

Abstract: An anti-vibration block is comprised of two substantially cylindrical coaxial end parts joined together by a cylindrical body coaxial with the end parts and of smaller section than these, the end parts and the cylindrical body defining a groove, a substantially cylindrical axial through-hole passing through the block, the end parts having on their outer faces opposite the groove pairs of projections of I and T-shape respectively.

Abstract: The fan comprises a central hub and a plurality of blades extending radially from the hub and each having a root portion adjacent the hub, a radially intermediate portion, and a radially outermost, tip portion. In the tip portion, the leading edge of each blade is inclined forwardly in the direction of rotation of the fan; in the root portion, the leading edge of each blade is inclined forwardly.

Abstract: The process makes it possible to detect the speed of rotation of a DC electric motor comprised of at least one winding connectable to a DC voltage supply source via an electronic switch with which there is associated a control circuit operable to provide a pulse width modulated square-wave control signal. The process comprises the operation of interrupting the application of the said control system to the electronic switch for a time period of pre-determined duration, acquiring during this time period a signal correlated to the voltage on the said winding and detecting at least one pre-determined characteristic of this signal in dependence on the speed of rotation of the motor.

Abstract: The system includes a sensor operable to supply electrical signals indicating the temperature of the engine and further sensors operable to supply electrical signals indicating predetermined parameters established to define operating conditions of the motor vehicle. A processing and control unit is provided to select, on the basis of the signals supplied by the said further sensors, a corresponding predetermined function which correlates the electric power to be supplied to the fan assembly with the electric power to be supplied to the electric pump, in dependence on the heat energy extracted from the engine, in order to obtain the minimum sum of the said electric power values; and to determine, on the basis of the signals supplied by the first sensor and the said selected function, the values of electric power to be supplied to the electric fan and the electric pump.

Abstract: The system includes a hydraulic circuit for supplying a flow of coolant to the engine, comprising a circulation pump, a radiator connected to the engine, a by-pass duct parallel to the radiator, and a regulating valve capable of adjusting the ratio of the flows of liquid supplied to the engine through the by-pass duct and the radiator respectively. The output of the circulation pump varies as a function of a control signal. A sensor provides signals indicating the temperature of the liquid flowing through a predetermined zone of the engine or the hydraulic circuit. An electronic unit connected to the sensor controls the pump such that the output of this latter varies depending on the temperature detected by the sensor. The regulating valve modifies the ratio of the aforesaid flows of liquid as the output of the pump varies.

Abstract: An axial fan in which the median line (B) of each blade (3) has a first radially-innermost, rearwardly-directed curved portion (B.sub.1) and a second radially-outermost, forwardly-directed curved portion (B.sub.2), the former portion being between 25% and 50% of the full radial extent of the blade. The profile of the blade is characterized in that its circular thickness (S) increases progressively from the interior to the exterior, and the pitch setting angle (W) of the profile decreases progressively from the interior to the exterior.