UNDERWATER MOTOR

PURPOSE:To improve the entire efficiency of an underwater motor pump by gradually varying a suction passage from a suction passage to the pump between a suction casing and a motor frame,and slowing varying the direction toward a motor shaft. CONSTITUTION:When a motor is energized and an impeller 39 is rotated, liquid fed into a suction casing 21 from many suction holes at the lower portion of the casing 21 rises in a suction passage 44. When rising, a flow passage sectional area of an upper flange of a motor frame 1 reduced, but since the flowing velocity is not normally fast here, and almost no flowing loss occurs. When arriving at the inlet of the passage 46 of the upper bracket 2, the flow of the liquid is directed toward an axial center, and the distance from the axial center to the suction passage becomes near. Accordingly, the sectional area gradually decreases to increase the flowing velocity, but the passages 46, 45 are smoothly coupled so that the direction is smoothly varied. Thus, it does not abruptly alter to reduce the fluid frictional loss.