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.