Abstract: A control system for a motor, including a first detector providing signals indicative of the sign and zero-crossings of a supply voltage, and a second detector providing signals indicative of the sign and the zero-crossings of BEMF developed in the stator winding. A switch is driven to cause a first current pulse through the winding at a first delay relative to the zero-crossing of the supply voltage. The system checks if the BEMF has a first zero-crossing within a predetermined period of time preceding a third zero-crossing of the voltage, and if so, causes an opposite second current pulse through the winding with a second delay relative to the third zero-crossing of the supply. If not, the first current pulse is repeated, reducing or increasing the duration of the first delay if the first zero-crossing of the BEMF took place after or before the predetermined period of time.

Abstract: The control system comprises a switch (TR) in series with a stator winding (W) between two terminals (A, B) connected to an alternating supply voltage source (V), a first detector circuit (2) capable of providing a signal (Voi) indicating when the current (I) in that winding (W) is zero, a second detector circuit (1) capable of providing a signal (Vw) indicating the magnitude of the supply voltage (V), and a control unit (MC) connected to the first and second detection circuits (2; 1) and designed to control the switch (TR) in such a way as to cause an alternating current (I) of the same frequency as the supply voltage (V) and having alternating positive and negative phases (11, 12) to pass through the winding (W), separated by intervals during which it remains at zero, of a duration (tp) which varies according to an increasing function of the magnitude of the supply voltage (V).

Abstract: The control system comprises a switch (TR) in series with a stator winding (W) between two terminals (A, B) connected to an alternating supply voltage source (V), a first detector circuit (2) capable of providing a signal (Voi) indicating when the current (I) in that winding (W) is zero, a second detector circuit (1) capable of providing a signal (Vw) indicating the magnitude of the supply voltage (V), and a control unit (MC) connected to the first and second detection circuits (2; 1) and designed to control the switch (TR) in such a way as to cause an alternating current (I) of the same frequency as the supply voltage (V) and having alternating positive and negative phases (11, 12) to pass through the winding (W), separated by intervals during which it remains at zero, of a duration (tp) which varies according to an increasing function of the magnitude of the supply voltage (V).

Abstract: The control system comprises: a switch (TR) in series with a winding (W) of the motor (M) between two terminals (A, B) which are connected to a supply of an alternating voltage (V), a first detector circuit (1) suitable for providing a signal (Vzc) indicative of the sign and of the zero-crossings of the alternating supply voltage (V), a second detector means (2, 3) suitable for providing signals indicative of the sign and of the zero-crossings of the BEMF which is developed in the stator winding (W), and a control unit (MC) arranged to bring about the starting of the rotation of the rotor (R), starting from an initial position (?0), in accordance with a procedure comprising the steps of: a) driving the switch (TR) in a manner such as to bring about the passage through the winding (W) of a first current pulse (I1) which starts with a first delay (t1) relative to the immediately preceding zero-crossing of the supply voltage (V), b) checking if the BEMF (E) consequently developed in the winding (W) has a first z

Abstract: An improved startup device for the rotor of a permanent-magnet synchronous motor, particularly adapted for liquid conveyance pumps, such as those used in electrical household appliances or the like, which are equipped with a permanent-magnet synchronous motor of the type comprising a stator unit with a pack of metal laminations and electrical windings supported by a body that forms a substantially cylindrical chamber that accommodates, upon assembly, the rotor unit, which is axially crossed by a motor shaft.