Draining lubricant from a hydrogen cooled generator

A hydrogen cooled generator 2 includes at least one lubricant drain system 20. The lubricant drain system includes a hydrogen detraining tank 34 having a hollow interior portion 42. A sensor 63 is operatively mounted in the hydrogen detraining tank. The sensor is configured and disposed to detect an interface zone 47 between an amount of lubricant and an amount of hydrogen gas in the hollow interior portion. A drain line 50 is fluidly coupled to the hydrogen detraining tank. The drain line includes a first end portion 52 that is exposed in the hollow interior portion and a second end portion 53. A valve 58 is mounted in the drain line. A controller 70 is operatively connected to the sensor and the valve. The controller is configured to selectively open the valve allowing a portion of lubricant to flow from the hollow interior portion when the interface zone is above the first end portion of the drain line. In other aspects, a lubricant drain system for a hydrogen cooled generator and a method of draining lubricant from a hydrogen cooled generator are claimed.