Method for contactless power transmission between a stationary part and a movable part , with an electrical power supply circuit comprising an air-coupled transformer provided with a primary resonant circuit with a primary coil supported by the stationary part and a secondary resonant circuit with a secondary coil facing the primary resonant circuit and supported by the movable part ; the method comprising the steps of - feeding the primary resonant circuit with a primary alternating electrical voltage (V 1 ) causing a primary electrical current (n) to circulate, said primary electrical current inducing in the secondary resonant circuit a secondary alternating electrical voltage (V 2 ) that causes a secondary electrical current (I 2 ) to circulate; - adjusting at least one electrical variable influencing the achievement of a resonance condition wherein the primary electrical voltage (V 1 ) is in phase with the primary electrical current (I 1 ); and - monitoring the distance (d) between the stationary part and the movable part , the method is characterized in that the step of monitoring the distance (d) between the stationary part and the movable part comprises: - detecting a value of said at least one electrical variable influencing the achievement of the resonance condition; and - determining said distance (d) between the stationary part and the movable part as a function of the value of said at least one electrical variable. the method comprising the steps of - feeding the primary resonant circuit with a primary alternating electrical voltage (V 1 ) causing a primary electrical current (n) to circulate, said primary electrical current inducing in the secondary resonant circuit a secondary alternating electrical voltage (V 2 ) that causes a secondary electrical current (I 2 ) to circulate; - adjusting at least one electrical variable influencing the achievement of a resonance condition wherein the primary electrical voltage (V 1 ) is in phase with the primary electrical current (I 1 ); and - monitoring the distance (d) between the stationary part and the movable part , - feeding the primary resonant circuit with a primary alternating electrical voltage (V 1 ) causing a primary electrical current (n) to circulate, said primary electrical current inducing in the secondary resonant circuit a secondary alternating electrical voltage (V 2 ) that causes a secondary electrical current (I 2 ) to circulate; - adjusting at least one electrical variable influencing the achievement of a resonance condition wherein the primary electrical voltage (V 1 ) is in phase with the primary electrical current (I 1 ); and - monitoring the distance (d) between the stationary part and the movable part , the method is characterized in that the step of monitoring the distance (d) between the stationary part and the movable part comprises: - detecting a value of said at least one electrical variable influencing the achievement of the resonance condition; and - determining said distance (d) between the stationary part and the movable part as a function of the value of said at least one electrical variable. - detecting a value of said at least one electrical variable influencing the achievement of the resonance condition; and - determining said distance (d) between the stationary part and the movable part as a function of the value of said at least one electrical variable. <EOS>