A method for monitoring the determination of a rotor angle (φ) of a rotating shaft by means of a resolver, - wherein the resolver comprises: - a first stator winding, - at least one second stator winding, whose winding axis is rotated through a predetermined angle with respect to the winding axis of the first stator winding, and - at least one rotor winding, which is connected to the rotating shaft such that they rotate together, - wherein the following steps are carried out for determination of the rotor angle: - a first, in particular sinusoidal, exciter AC voltage ( U e1) at an exciter frequency ( f e) and with a first amplitude (sinφ) is applied to the first stator winding, - a second, in particular sinusoidal, exciter AC voltage ( U e2) at the exciter frequency and with a second amplitude (cosφ) is applied to the at least one second stator winding, and - the first amplitude and the second amplitude are produced by means of a regulator such that no voltage is induced in the at least one rotor winding as a result of the first and the second exciter AC voltages in a stationary state, wherein a manipulated variable of the regulator maps the rotor angle, - wherein the following steps are carried out for monitoring the determination of the rotor angle: - a first, in particular sinusoidal, test AC voltage ( U t1) at a test frequency ( f t) which is not the same as the exciter frequency is applied to the first stator winding, and - a second, in particular sinusoidal, test AC voltage ( U t2) at the test frequency is applied to the at least one second stator winding, wherein the first and the second test AC voltages are produced in response to the rotor angle such that a magnetic alternating field which is produced as a result of the first and the second test AC voltages runs essentially parallel to the winding axis of the rotor winding, so that an AC voltage is permanently induced in the at least one rotor winding as a result of the first and the second test AC voltages. - wherein the resolver comprises: - a first stator winding, - at least one second stator winding, whose winding axis is rotated through a predetermined angle with respect to the winding axis of the first stator winding, and - at least one rotor winding, which is connected to the rotating shaft such that they rotate together, - a first stator winding, - at least one second stator winding, whose winding axis is rotated through a predetermined angle with respect to the winding axis of the first stator winding, and - at least one rotor winding, which is connected to the rotating shaft such that they rotate together, - wherein the following steps are carried out for determination of the rotor angle: - a first, in particular sinusoidal, exciter AC voltage ( U e1) at an exciter frequency ( f e) and with a first amplitude (sinφ) is applied to the first stator winding, - a second, in particular sinusoidal, exciter AC voltage ( U e2) at the exciter frequency and with a second amplitude (cosφ) is applied to the at least one second stator winding, and - the first amplitude and the second amplitude are produced by means of a regulator such that no voltage is induced in the at least one rotor winding as a result of the first and the second exciter AC voltages in a stationary state, wherein a manipulated variable of the regulator maps the rotor angle, - a first, in particular sinusoidal, exciter AC voltage ( U e1) at an exciter frequency ( f e) and with a first amplitude (sinφ) is applied to the first stator winding, - a second, in particular sinusoidal, exciter AC voltage ( U e2) at the exciter frequency and with a second amplitude (cosφ) is applied to the at least one second stator winding, and - the first amplitude and the second amplitude are produced by means of a regulator such that no voltage is induced in the at least one rotor winding as a result of the first and the second exciter AC voltages in a stationary state, wherein a manipulated variable of the regulator maps the rotor angle, - wherein the following steps are carried out for monitoring the determination of the rotor angle: - a first, in particular sinusoidal, test AC voltage ( U t1) at a test frequency ( f t) which is not the same as the exciter frequency is applied to the first stator winding, and - a second, in particular sinusoidal, test AC voltage ( U t2) at the test frequency is applied to the at least one second stator winding, wherein the first and the second test AC voltages are produced in response to the rotor angle such that a magnetic alternating field which is produced as a result of the first and the second test AC voltages runs essentially parallel to the winding axis of the rotor winding, so that an AC voltage is permanently induced in the at least one rotor winding as a result of the first and the second test AC voltages. - a first, in particular sinusoidal, test AC voltage ( U t1) at a test frequency ( f t) which is not the same as the exciter frequency is applied to the first stator winding, and - a second, in particular sinusoidal, test AC voltage ( U t2) at the test frequency is applied to the at least one second stator winding, wherein the first and the second test AC voltages are produced in response to the rotor angle such that a magnetic alternating field which is produced as a result of the first and the second test AC voltages runs essentially parallel to the winding axis of the rotor winding, so that an AC voltage is permanently induced in the at least one rotor winding as a result of the first and the second test AC voltages.