%0 Journal Article %T Forces Between Conductors: The "50/50 Rule"; About the Partition of Supplied Energy %+ Laboratoire Génie électrique et électronique de Paris (GeePs) %A Bossavit, Alain %< avec comité de lecture %@ 0018-9464 %J IEEE Transactions on Magnetics %I Institute of Electrical and Electronics Engineers %V 51 %N 3 %P 8202504 %8 2015-03 %D 2015 %R 10.1109/TMAG.2014.2359915 %Z Physics [physics]Journal articles %X We prove the 50/50 rule of Fig. 1 by a Lagrangian technique (all fields pulled back to the reference configuration at time 0) which exposes the necessity of two circumstances for the result to hold: 1) time-invariance of currents, when expressed in “material form” and 2) equality of (magnetic) coenergy and energy, which excludes nonlinear B-H laws. A dual result, which holds in case of time-invariance of “flux linkages” (but without the linearity restriction), is found along the way. %G English %L hal-01310838 %U https://centralesupelec.hal.science/hal-01310838 %~ UPMC %~ CNRS %~ UNIV-PSUD %~ CENTRALESUPELEC %~ GEEPS %~ PIEM %~ UNIV-PARIS-SACLAY %~ UNIV-PSUD-SACLAY %~ CENTRALESUPELEC-SACLAY %~ UPMC_POLE_1 %~ SORBONNE-UNIVERSITE %~ SU-SCIENCES %~ GS-ENGINEERING %~ GS-PHYSIQUE %~ INSTITUT-SCIENCES-LUMIERE %~ ALLIANCE-SU %~ TEST3-HALCNRS