Abstract: To nondestructively diagnose a weight reduction ratio of an insulating material or a lubricating oil without stopping operation of the equipment, a nondestructive diagnostic method uses an optical fiber probe type sensor in which a light transmission loss or a reflective absorbance difference is used as a parameter.

Abstract: A highly thermal-conductive and thermal-resistant electrically insulated coil with less outflow of a thermosetting resin composition can be produced, to provide a small-scale, light-weight rotating machine with high power. The thermosetting resin composition comprises (a) a polyfunctional epoxy resin containing three or more p-(2,3-epoxypropoxy) phenyl groups and a group represented by the Chemical formula 1; or an epoxy resin with a naphthalene backbone, represented by the Chemical formula 3, 4 or 5 or an epoxy resin with an anthracene backbone, such as diglycidyl ether of anthracene diol and triglycidyl ether of anthracene triol; (b) a bifunctional epoxy resin containing two p-(2,3-epoxypropoxy) phenyl groups; (c) an acid anhydride curing agent; and (d) a metal acetonate curing catalyst represented by the Chemical formula 2 at 0.1 to 5 parts by weight per 100 parts by weight of the epoxy resins.

Abstract: A thermosetting resin composition comprising:[A] a polyfunctional epoxy resin produced from a reaction between a mixture of at least two polyhydric phenols selected from (a) bis(4-hydroxyphenyl)methane, (b) bis(4-hydroxyphenyl)ethane, (c) bis(4-hydroxyphenyl)-propane, (d) tris(4-hydroxyphenyl)alkane and (e) tetra(4-hydroxyphenyl)alkane, and epichlorohydrin, and[B] an acid anhydride curing agent; and a coil and a panel formed of said composition.

Abstract: An epoxy resin composition for insulating a coil which comprises at least one polyfunctional epoxy resin, at least one latent curing catalyst, at least one filler and at least one surfactant, wherein the ceiling is set to the acid anhydride content in the composition at 10% by weight based on the weight of the epoxy resin; and a coil molded out of said resin composition.

Abstract: A thermoplastic resin composition for casting high-voltage coils containing two kinds of fillers (A) and (B), and products as molded coils and panels obtained by casting and curing the composition.The composition of the present invention contains 60%-85% by weight, based on the total weight of the composition, of a silica type filler which is an admixture (A) a spherical silica having an average particle diameter of 0.1-0.9 .mu.m and (B) a ground silica having an average particle diameter of 3-9 .mu., the ratio A/(A+B) being 1%-7% by weight.Products as molded coils and panels prepared by using the composition have good resistance to cracking and resistance to moisture.

Abstract: An electrically insulated coil manufactured with a composition comprising a poly-functional epoxy resin having at least three of p-(2,3-epoxy propoxy) phenyl groups and a bi-functional epoxy resin as a binding resin for a reinforced insulating base sheet and as an impregnation resin has no peeling off in its insulating layers and is capable to be used continuously under the temperature at 200.degree. C. or above.

Abstract: An insulator for covering electric conductors is used to cover, for the purpose of providing insulation, lead wires of the coils in rotary electric machines or stationary induction motors or conductors for connecting various electrical machinery and apparatus. The insulator is comprised of a flexible plastic film tube provided with a soft material on its inner surface. Such a construction prevents the insulation from being damaged even if the electric conductor has corners or bends or even if an external force is applied to the electric conductor because the soft material is compressed and deformed to absorb the applied force.

Abstract: An electromagnetic apparatus in which a semiconductive liner of which at least one side is processed by mold releasing material is provided between the winding embedded in the slots of an iron core and the wall of the slot, and the remainder of the slots is filled with adhesive. The liner employed prevents the winding from adhering to the wall of the slot with the result that the insulating layer of winding is not damaged during thermal cycling and also corona discharge is prevented.