A liquid cooled rectified-alternating current generator for supplying direct current to electrical loads such as the battery and other electrical loads on a motor vehicle. The generator has a generator compartment containing a stator winding and a rotor. A rectifier compartment is provided at the end of the generator which contains diode rectifiers supported by heat sinks and connected to the stator winding of the generator. A liquid coolant medium, such as engine lubricating oil, is circulated through the generator. The coolant is supplied under pressure to the rectifier compartment, thence to the generator compartment and from there coolant is exhausted into a suitable oil sump. The passage means for supplying coolant from the rectifier compartment to the generator compartment comprises a laterally extending passage having an inlet located adjacent the heat sinks for the rectifiers. The length and position of the passage is such that in any rotative position of the generator sufficient oil is maintained in the rectifier compartment to contact at least one of the heat sinks for the rectifiers. Thus, when the fluid pressure system is shut down the rectifier compartment will retain a certain amount of coolant so that subsequent operation of the generator will not cause destruction of the rectifiers due to overheating.