A method for determining at least one characteristic quantity of an asynchronous electric machine in operation, the machine comprising at least one stator and a rotating rotor relative to the stator about an axis coincident with the longitudinal axis of the machine, the stator comprising at least two poles, and radiating, in operation, in at least one first set of points located around the outer surface of the machine, a magnetic field having an axial component oriented parallel to said axis, and in at least a second set of points located around the outer surface of the machine, a magnetic field having a tangential component defined along a direction contained in a plane transverse to said axis and oriented perpendicular to the line passing, in this plane, through one of the points of said second set of points and said axis, the method comprising a calibration phase then an evaluation phase of at least one characteristic quantity: - the calibration phase comprising: o a first step of measuring, at said first set of points, the axial component and simultaneously, at said second set of points, the tangential component, as well as the phase shift between the axial component and the tangential component, for a plurality of intensity values absorbed by the machine, o from the results of the first measuring step, a step of constructing a calibration curve under the form of a straight line linking the absorbed intensity and the axial component, said construction step comprising a step of determining a no-load operation binomial characterized by an amplitude of the no-load axial component and an absorbed no-load intensity, and a step of determining a second operation binomial characterized by a second amplitude of axial component and a second absorbed intensity, o said step of determining a no-load operation binomial further comprising a step of determining of a no-load operation field and of a point of this field characterized by an amplitude of no-load tangential component and an amplitude of no-load axial component measured simultaneously at the first measuring step, - the evaluation phase comprising: o a second step of measuring, at an operation point, the axial component, the tangential component, and the phase shift between the tangential component and the axial component, o a step of determining, at the measured operation point, at least one characteristic quantity of the machine from the values measured in the second measuring step, using the calibration curve. - the calibration phase comprising: o a first step of measuring, at said first set of points, the axial component and simultaneously, at said second set of points, the tangential component, as well as the phase shift between the axial component and the tangential component, for a plurality of intensity values absorbed by the machine, o from the results of the first measuring step, a step of constructing a calibration curve under the form of a straight line linking the absorbed intensity and the axial component, said construction step comprising a step of determining a no-load operation binomial characterized by an amplitude of the no-load axial component and an absorbed no-load intensity, and a step of determining a second operation binomial characterized by a second amplitude of axial component and a second absorbed intensity, o said step of determining a no-load operation binomial further comprising a step of determining of a no-load operation field and of a point of this field characterized by an amplitude of no-load tangential component and an amplitude of no-load axial component measured simultaneously at the first measuring step, o a first step of measuring, at said first set of points, the axial component and simultaneously, at said second set of points, the tangential component, as well as the phase shift between the axial component and the tangential component, for a plurality of intensity values absorbed by the machine, o from the results of the first measuring step, a step of constructing a calibration curve under the form of a straight line linking the absorbed intensity and the axial component, said construction step comprising a step of determining a no-load operation binomial characterized by an amplitude of the no-load axial component and an absorbed no-load intensity, and a step of determining a second operation binomial characterized by a second amplitude of axial component and a second absorbed intensity, o said step of determining a no-load operation binomial further comprising a step of determining of a no-load operation field and of a point of this field characterized by an amplitude of no-load tangential component and an amplitude of no-load axial component measured simultaneously at the first measuring step, - the evaluation phase comprising: o a second step of measuring, at an operation point, the axial component, the tangential component, and the phase shift between the tangential component and the axial component, o a step of determining, at the measured operation point, at least one characteristic quantity of the machine from the values measured in the second measuring step, using the calibration curve. o a second step of measuring, at an operation point, the axial component, the tangential component, and the phase shift between the tangential component and the axial component, o a step of determining, at the measured operation point, at least one characteristic quantity of the machine from the values measured in the second measuring step, using the calibration curve.