Winding for linear pump

A winding and method of winding for a submersible linear pump for pumping liquid sodium is disclosed. The pump includes a stator having a central cylindrical duct preferably vertically aligned. The central vertical duct is surrounded by a system of coils in slots. These slots are interleaved with magnetic flux conducting elements, these magnetic flux conducting elements forming a continuous magnetic field conduction path along the stator. The central duct has placed therein a cylindrical magnetic conducting core, this core having a cylindrical diameter less than the diameter of the cylindrical duct. The core once placed to the duct defines a cylindrical interstitial pumping volume of the pump. This cylindrical interstitial pumping volume preferably defines an inlet at the bottom of the pump, and an outlet at the top of the pump. Pump operation occurs by static windings in the outer stator sequentially conveying toroidal fields from the pump inlet at the bottom of the pump to the pump outlet at the top of the pump. The winding apparatus and method of winding disclosed uses multiple slots per pole per phase with parallel winding legs on each phase equal to or less than the number of slots per pole per phase. The slot sequence per pole per phase is chosen to equalize the variations in flux density of the pump sodium as it passes into the pump at the pump inlet with little or no flux and acquires magnetic flux in passage through the pump to the pump outlet.

What is claimed is:

1. In a linear pump for pumping liquid sodium, the pump having a cylindrical stator, a cylindrical central duct concentrically fastened to said stator, a central magnetic field conducting core fastened central to said cylindrical central duct, said central magnetic field conducting core having a diameter less than the diameter of said cylindrical central duct whereby said cylindrical central duct and said central magnetic field conducting core define together an interstitial cylindrical pumping volume having an inlet and an outlet, means for conducting a magnetic field disposed in said stator about said central duct; and powered coil means spatially distributed in said means for conducting a magnetic field in said stator; the improvement is said powered coil means including:

a power supply having at least two alternating phases;

a group of coils in side by side relation along said stator and disposed around said central duct for generating a magnetic field to said means for conducting a magnetic field;

said coils defining at least three poles;

each said pole defined by a plurality of coils for each phase, said plurality of coils being in a sequential order and each having varying phase angles responsive to said power supply; and,

a plurality of parallel connections, each parallel connection including at least one coil from one phase on each pole whereby flux variations along the central duct in said pumped sodium are averaged between said parallel connections; and,

each parallel connection further including a permuted sample of the coils of each phase of each pole whereby differing phase angles from differing coils in differing poles are averaged in each parallel connection to reduce circulating currents in said parallel connections.

2. The invention of claim 1 and wherein said coils define at least eight poles and wherein each said pole is defined by four coils for each phase and wherein said power supply has three phases.

3. The invention of claim 2 and wherein said plurality of parallel connections includes four parallel connections for each phase.

4. In a linear stator disposed along a linear axis, said stator having a magnetic field conducting core disposed along said axis and a plurality of power winding means spatially distributed, along said axis across said linear axis in said means for conducting a magnetic field in said stator; the improvement in said power winding means including:

a power supply having at least two alternating phases;

a group of windings in side-by-side relation the length of said stator and crossing the linear axis of said stator for generating a magnetic field to said magnetic field conducting core;

said windings defining at least three poles;

each said pole defined by a plurality of windings for each phase, said plurality of windings for each phase being in sequential order and each having varying phase angles responsive to said power supply; and a plurality of parallel connections, each parallel connection including at least one winding from one phase on each pole whereby flux variations along the linear length of said stator are averaged between said parallel connections; and, each parallel connection further including a permuted sample of the windings of each phase of each pole whereby differing phase angles from differing windings in differing poles are averaged in each parallel connection to reduce circulating currents in said parallel connections.

5. The invention of claim 4 and wherein said windings comprise coils.

6. The invention of claim 5 and wherein said stator is disposed about a cylindrical duct.