Mitsubishi Denki Kabushiki Kaisha

Nobuo Sonoda

Mitsuhiro Nishida

Sakuei Yamamoto

Noboru Tashiro

Kazuo Okahashi

Shoji Takagi

A molding material having low moisture permeability for use in the stators of submersible motors. The molding material comprises approximately 20-30 parts by weight of an epoxy resin, approximately 1-3 parts by weight of a curing agent, approximately 0.5-1.5 parts by weight of zinc stearate, approximately 2-3 parts by weight of a mechanical reinforcing agent, approximately 7.5-56.5 parts by weight of quartz powder, and one or more substances selected from anhydrous gypsum and silica gel, with the total amount of said inorganic substance(s) being approximately 55-20 parts by weight, and with the total amount of quartz powder and said inorganic substance(s) being approximately 62.5-76.5 parts by weight. Because of its low moisture permeability, the insulating properties of the molding material can be maintained indefinitely.

Molding material for the stator of a submersible motor

The stator core having stator coils thereon of a submersible electric motor is provided with a cylindrical can disposed in engagement with the inner surface of the stator coil and molded resin member is formed completely about the external surface of the core, the end surfaces of the core and the end portions of the coils in engagement with the end portions of the can to completely encapsulate the core and coils. The end portions of the can may be bent outwardly and embedded directly in the molded resin member during the molding thereof with the can located within the core. Alternatively, a mold tool may be located within the core for molding the molded resin member about the stator core and coils and upon removal of the tool a hollow cylindrical can may be located within the core. The end portions of the can are then sealed to the end portions of the molded member. A terminal plate and fastener fittings may also be molded integrally into the molded member. End brackets may then be secured to opposite ends of the molded resin member. The brackets are provided with bosses which extend into the can and a seal is provided between the can and the boss. The can, in conjunction with the end brackets, define a central portion for receiving a lubricant for the bearings supporting a rotor within the can.

Submersible electric motor and method of manufacturing the same

A molded submersible well motor comprises a hollow cylindrical frame 5 formed of resinous molding material into which a stator assembly having stator cores 2 and coils 3 is molded. End brackets 8 also formed of resinous molding material are detachably secured to opposite ends of the frame to close the openings thereof. A starting switch 12 for the motor is molded into the upper end bracket, together with an interconnecting terminal 9 comprising upper and lower contact posts 91, 92 for connecting the power cable 10 to the stator coils via a connector 6 and an intermediate connector 11, and a sub-receptacle 901, 930 projecting outwardly perpendicular to the main terminal 9 for connection to the starting switch.

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Fukuoka, Japan

Nobuo Sonoda