Electrical generator and method for operating a cooling circuit of an electrical generator

The electrical generator (1) comprises a stator (2) and a rotor (3) housed within the stator (2). The stator (2) is provided with a cooling circuit comprising a pump (6) pumping a cooling liquid through a pipe (7) provided with a plurality of branches (9) passing through the stator (2). The cooling circuit comprises a sensor (10) for measuring the temperature of the cooling liquid connected to a control unit (11) that is connected to and drives the pump (6). When the sensor (10) measures a cooling liquid temperature higher than a prefixed temperature, the control unit (11) increases the cooling liquid flow rate to increase the heat that the cooling liquid takes up from the stator (2), and when the sensor measures a cooling liquid temperature lower than said prefixed temperature the control unit decreases the cooling liquid flow rate to decrease the heat that the cooling liquid takes up from the stator (2). The present invention also refers to a method for operating the cooling circuit of an electrical generator.