Gravity oil return device for testing oil-cooled motor

The utility model relates to the technical field of oil-cooled motor testing, and discloses a gravity oil return device for oil-cooled motor testing, which comprises a tested motor, and a testing mechanism is arranged on the left side of the tested motor. According to the gravity oil return device for testing the oil-cooled motor, oil in the tested motor flows into the gravity oil collecting tank by means of natural gravity, then the pumpback pump sucks the oil in the gravity oil collecting tank and pumps the oil back to the circulating oil tank, inlet and outlet balance is achieved, the frequency of the pumpback pump is automatically adjusted through liquid level feedback of the gravity oil collecting tank, and the pumpback pump can be prevented from sucking air; if the oil suction pump sucks part of bubbles, the bubbles can exhaust gas into the expansion oil tank through the oil-gas separation device behind the pump, the gas is prevented from entering an oil way to the greatest extent and is supplied to a r