Patent ID: 8179083

Claim:
Starting device for electric motors, more particularly for use with motors of compressors, comprising: a relay ( 4 ) in series with a resistive element ( 15 ); a starting capacitor ( 6 ) and a run capacitor ( 7 ) respectively connected in series and in parallel to said relay ( 4 ); and a circuit comprising: a first branch ( 9 ) connected at one end to a common point (P) and at the opposite end to the start winding ( 1 ) of the motor, with said starting capacitor ( 6 ), said resistive element ( 15 ) and the fixed contacts ( 8 ) of said relay ( 4 ) being inserted in series in said first branch ( 9 ); a second branch ( 10 ), in parallel with the first branch ( 9 ), connected at one end to the common point (P) and at the opposite end to the main or run winding ( 2 ) of the motor, with the coil ( 11 ) of the relay ( 4 ) being inserted in said second branch ( 10 ); and a third branch ( 14 ), in parallel with said first ( 9 ) and said second ( 10 ) branch, connected at one end to the common point (P) and at the opposite end to the start winding of the motor, with said run capacitor ( 7 ) being installed in said third branch ( 14 ); wherein the common point (P) is connected to the common connector (C) of the motor via the power supply line ( 3 ); and wherein said resistive element ( 15 ) is an NTC resistor, whereby, when the power supply to the electric motor is activated, said NTC resistor ( 15 ), being still at ambient temperature, is inhibited and prevents the current peak generated by the capacitors from traversing the contacts ( 8 , 13 ) of the relay ( 9 ), and then the same NTC resistor, when heated due to the adsorbed current peak, allows the passage of the stabilised current via said contacts ( 8 , 13 ) and therefore the starting of the electric motor.