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A dynamoelectric machine having a stator housing or frame made by a lost foam process utilizing a unitary single-piece vaporizable pattern. The stator housing may be made from a molten metal such as cast iron or aluminum, and has an annular wall having integral outwardly extending longitudinal cooli

A dynamoelectric machine having a stator housing or frame made by a lost foam process utilizing a unitary single-piece vaporizable pattern. The stator housing may be made from a molten metal such as cast iron or aluminum, and has an annular wall having integral outwardly extending longitudinal cooling fins, mounting foots pads and a conduit box support pad. The lost foam process enables the cooling fins to have a greater effective cooling fin height to housing diameter ratio and greater effective cooling fin height to housing annular wall thickness ratio than obtained with prior sand casting processes. The greater height fins provide increased strength and rigidity for the annular wall which can be made radially thinner than prior stator housing or frames of similar size. Substantial savings in material and labor are realized by the stator housing.

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A method for making an integral single piece stator frame for use in a dynamoelectric machine, wherein the stator frame comprises a housing having a generally annular wall defining an axial bore and having a plurality of external longitudinally extending cooling fins integral with the annular wall,

A method for making an integral single piece stator frame for use in a dynamoelectric machine, wherein the stator frame comprises a housing having a generally annular wall defining an axial bore and having a plurality of external longitudinally extending cooling fins integral with the annular wall, said method comprising the steps of; a. forming an integral single piece vaporizable pattern having a configuration substantially identical to the stator frame and being capable of vaporization when contacted by a molten metal; b. forming a coating on the full surface of the pattern which is gas permeable but will not vaporize when contacted by said molten metal, c. burying the coated pattern in sand in a manner enabling molten metal to be poured into contacting relation with the pattern, d. pouring a sufficient quantity of molten metal into contacting relation with the pattern to vaporize the pattern and fill the resulting void with molten metal so as to define a molten metal annular wall and external longitudinal cooling fins establishing a ratio of effective cooling fin height over the outer diameter of said annular wall in the range of approximately 4.0-6.0, e. allowing the molten metal to solidify and cool to thereby form a single piece stator frame casting, and f. removing the casting from the sand.