Patent ID: 7471058

Claim:
A starting device for a single phase induction motor comprising: a stator having a running coil and a starting coil; a power source which supplies current to said running coil and said starting coil; a running switch and a starting switch, respectively connecting the running coil and the starting coil to the power source when in a closed condition, said starting switch being conducted to an open condition upon completion of the motor start; a current sensor connected in series between the power source and the stator, in order to detect the current level supplied to the latter; and a control unit supplied by the power source and receiving, from the current sensor, signals representative of the current level being supplied to the stator, wherein said control unit is operatively connected to the running switch and to the starting switch, in order to instruct the open and closed conditions thereof, the open condition of the starting switch being defined when the ratio (K) between the present current level (Ia) supplied to the stator and informed by the current sensor to the control unit and the starting current level (Ip) previously informed to said control unit by the current sensor upon the closing of the starting and the running switches, so that when said ratio K reaches a value that is equal or inferior to a predetermined value (Km) the control switch instructs the opening of the starting switch, wherein the value of Km is constantly adjusted.