Motor system , having - a stator , - a rotor , - a number of power modules which each have planar contact faces for dissipating heat, - a control device which is designed to actuate the power modules , - a housing , wherein the stator and the rotor are arranged inside the housing , and - at least one heat sink , - wherein the heat sink has a number of planar contact faces which are connected in a thermally conductive fashion to respectively corresponding contact faces of the power modules , and - wherein the heat sink has regions for dissipating heat, wherein a coolant flows around the regions in order to dissipate heat, - wherein the stator and the rotor are arranged in a first axial section of the housing , - wherein the heat sink is inserted into a second axial section , different from the first axial section , inside the housing , - wherein the housing has: - a first central duct , wherein the stator and the rotor are arranged inside the first duct , and - a number of second ducts , wherein the second ducts surround the first duct radially, and wherein the second ducts form closed ducts for conducting the coolant, - wherein the first duct and the second ducts extend only over the first axial section of the housing , characterized in that - the heat sink is inserted into the housing between an active part consisting of the stator and the rotor and a B end plate, and - the motor system has a thermally insulating intermediate element , wherein the intermediate element is arranged between the first axial section and the second axial section . - a stator , - a rotor , - a number of power modules which each have planar contact faces for dissipating heat, - a control device which is designed to actuate the power modules , - a housing , wherein the stator and the rotor are arranged inside the housing , and - at least one heat sink , - wherein the heat sink has a number of planar contact faces which are connected in a thermally conductive fashion to respectively corresponding contact faces of the power modules , and - wherein the heat sink has regions for dissipating heat, wherein a coolant flows around the regions in order to dissipate heat, - wherein the stator and the rotor are arranged in a first axial section of the housing , - wherein the heat sink is inserted into a second axial section , different from the first axial section , inside the housing , - wherein the housing has: - a first central duct , wherein the stator and the rotor are arranged inside the first duct , and - a number of second ducts , wherein the second ducts surround the first duct radially, and wherein the second ducts form closed ducts for conducting the coolant, - wherein the first duct and the second ducts extend only over the first axial section of the housing , - a first central duct , wherein the stator and the rotor are arranged inside the first duct , and - a number of second ducts , wherein the second ducts surround the first duct radially, and wherein the second ducts form closed ducts for conducting the coolant, - wherein the first duct and the second ducts extend only over the first axial section of the housing , - the heat sink is inserted into the housing between an active part consisting of the stator and the rotor and a B end plate, and - the motor system has a thermally insulating intermediate element , wherein the intermediate element is arranged between the first axial section and the second axial section . <EOS>