| 摘要 |
The device (10) comprises two supply terminals (11, 12) intended to be connected to an alternating supply source, a switching circuit (13) connected to an end terminal (B) and to the intermediate tapping (C) of the stator winding (5) and operable to assume a first and then a second condition in which it allows coupling to the voltage source of a the first portion (L1) of the stator winding (5) and the entire winding (5) respectively; a timer circuit (14) coupled to the switching circuit (13) and operable to cause it to pass from the first to the second condition after a reference time period of application of voltage to the supply terminals (11, 12,) and a synchronisation circuit (15) coupled to a rotor position sensor (16) and arranged to control the current at least in the first portion (L1) of the stator winding (5) in a predetermined manner in dependence on the polarity on the voltage delivered from the source and the position of the rotor (2) in order to cause in the starting phase of the motor (1), the rotor (2) to rotate at an increasing speed until reaching, in a time less than or equal to the said reference time period, a synchronisation speed corresponding to the frequency of the alternating supply voltage. <IMAGE> |
