Abstract: An electrically insulating board suitable inter alia for use as printed circuit board is made by impregnating a stitch bonded fabric comprising high temperature fibres such as Nomex (RTM) and curing the resin by hot pressing.

Abstract: A fabric is resin-impregnated by placing it between a liquid resin surface and an evacuated space. The fabric can be laid on top of or passed continuously over a liquid resin surface, the resin being heated to a temperature at which it flows readily. A pre-preg produced according to the method can be laminated with other pre-preg or fabric layers into board, but several fabric layers can be impregnated together to form a thick pre-preg.

Abstract: A shaper for the coils of large rotary electric machines bends an elongate loop coil blank so that the inwardly-directed faces (15) of the straight parallel sections are turned downwardly so that the ends (14) of the coil "kink" downwardly, thereby making possible a downwardly directed mallet blow for initiating kinking of the ends 14 in the correct direction.

Abstract: A composite insulating material for the coils of large rotating electric plant comprises a central layer of resinous mica paper between outer layers of high temperature textile material, such, for example, as stitch bonded high temperature nylon fibres. The material may be provided in the form of a channel section which, with a complementary such section, fits over a straight slot-fitting section of the coil in the form of a sleeve, which may be consolidated on the coil by a coil pressing operation.

Abstract: This invention relates to the stitch-bonded high temperature fabric insulation of the coils of rotating electric machinery, particularly large rotating machinery such as generators and medium to large motors, and is concerned not only with such insulation during manufacture of the machinery but also with the rewinding of such machinery for repair or refurbishment.

Abstract: The wrapped insulation on the straight parallel sections of coils for larger rotary electric machines is treated under heat and pressure in a preferably double-sided coil press in which pressure is applied first to the center of the heated sections then also to the outer parts thereof to enable excess resin impregnating the insulation to flow away from the center parts and achieve a more uniformly and accurately dimensioned coil.

Abstract: The wrapped insulation of coils of large electric machines--motors or generators--is set by heat and pressure in a press that extends the length of both wrapped legs of the coil and supports the coil so that it is substantially free from stress. The coil may be supported with its wrapped legs level and horizontal, and the press can be adjustable for different coil sizes and configurations. The heat and pressure cycle is operable automatically to suit the requirements of the insulating material.