In Quantum Physics the Spin of an elementary particle is defined to be an „intrinsic, inherent“ property. The same to the magnetic moment (μ) due to the spin of charged particles - like Electron (me) and Proton (mp). So the intrinsic spin (S=1/2h-bar) of the electron entails a magnetic moment because of charge (e). However, a magnetic moment of a charged particle can also be generated by a circular motion (due to spin) of an electric charge (e), forming a current. Hence the „orbital motion of charge“ around a „mass-nucleus“ generates a magnetic moment by Ampère’s law. This concept leads to an alternative way calculating the neutrino mass (mν) while discussing the beta decay of a neutron into fragments: proton, electron, neutrino and binding energy. The change of neutrons magnetic moment (μn) during the decay process based on energy and spin and charge conservation should allow to calculate the restmass of the neutrino. (KATRIN <1.1eV (2019) about 0.2eV (2021). Estimation from μn: 0.10(20)eV (2020).