To　both　overcome　the　serious　thermal　recession　problem　and　conserve　energy　for　conventional　eddy-current　brakes,　a　self-excited　and　liquid-cooled　electromagnetic　retarder　(SL-EMR)　assembly　is　proposed.　The　design　includes　a　stator　with　an　internally　cooled　channel,　a　rotor　with　multiple　magnetic　heads,　and　an　integrated　generator　without　brushes.　The　assembly　and　operating　principles　are　analyzed.　Models　of　the　braking　and　generating　systems　are　established.　The　electromagnetic　field　model　analysis,　braking　performance　analysis,　thermal　field　analysis,　and　generator　characteristic　analysis　of　the　SL-EMR　are　simulated　using　the　finite-element　method　(FEM).　The　SL-EMR　performance　is　bench　tested,　and　the　results　show　a　6%　difference　between　the　FEM　results　and　the　experimental　results.　The　integrated　generator　provides　adequate　exciting　current　for　the　braking　system.　The　braking　torque　decreases　by　only　10.4%　during　continuous　braking　conditions.　The　braking　torque　reached　2000　N　.　m　when　the　speed　was　1500　r/min　and　the　coil　current　was　30　A.