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.