A dynamoelectric machine having a quiet cooling system. The system comprises at least twenty-five short chord axially mounted radial blades disposed on a conical hub which is disposed on the rotor of the dynamoelectric machine. The arrangement and number of blades are such that the coolant flow is increased while the pure tone noises are reduced thus increasing cooling and reducing subjective annoyance. A conical shroud encloses the conical hub defining therebetween a conical annulus whose total annular cross-sectional area does not expand to the point where turbulence and flow separation would occur. A bell-mouthed protective grilled inlet is disposed on the conical shroud for conducting a coolant, under the action of the rotating blades, through the bell-mouthed inlet and into the conical annulus. The bell-mouthed inlet and conical annulus together providing a streamlined path for quietly diffusing the coolant into the proximity of surfaces susceptible to heating.