GB877377A - Improvements in or relating to electric motors of the submersible type - Google Patents

Abstract

877,377. Pump motors. HAYWARD TYLER & CO. Ltd. Jan. 22, 1958 [Oct. 22, 1956], No. 32111/56. Class 35. In a motor-driven pump unit in which the pumped liquid has access to the motor rotor, the stator is sealed off by a diaphragm 15 passing through the air gap and is immersed in a separate cooling liquid. The liquid which is pumped by impeller 5 has access to the interior of the motor casing 7 through a heat-transfer reducing barrier 14 which fits loosely round the motor shaft 4. The liquid in the motor casing is circulated by means of an impeller 13 so that it passes vertically through journal bearings 10, 11 and thrust bearing 12, which bearings may be of the tilting pad type, and also circulates by pipes 20, 21 to an external cooler (not shown). The stator 2 is enclosed in a non-magnetic can comprising the diaphragm 15 and end covers 16, 17, and containing oil. This oil may be separately cooled after passing up through the stator slots by circulation through cooling tubes 31 by a small motor-driven pump 22a on a sealed partition disc 22 within the stator can. The tubes 31 are surrounded by a cooling jacket 32 through which cooling water is circulated. In a modification, the tubes 31 are cooled by means of a jacket through which the cooling water for the main motor is circulated. In a further modification, the outside cooler is dispensed with, and the pump 22a merely circulates the coil through tubes passing through the partition 22 and passing down through slots in the outer periphery of the stator pack. Pump 22a, Fig. 2, comprises a vertical rotor 23 mounted on integral trunnions 25, 26 and having an axial hole 29 and radial holes 30 which produce a pumping action on rotation of the rotor. The leads 39 which supply the main motor pass through slots in the stator pack 24 to form stator windings, the leads of each phase being 180 degrees apart.