Abstract: Insulating slot liners for insertion into stator core winding slots are formed from a narrow-width reel of insulating material. The width of the material is determined by the inner circumferential surface of the winding slot that must be insulated, instead of being based on the axial length of the stator core as has been the practice in the past. As a result, slot liners may be easily produced for stator cores of different axial lengths by simply adjusting the length of material cut from the reel. Preferably, the cutting mechanism used to cut the length of material is adapted to form a pair of opposed cuffs when the material is cut. An insulator blank formed in this manner is pushed into a die, thereby forming a U-shaped slot liner. A transfer mechanism functions to move the slot liner into a respective winding slot. The slot liner preferably passes through a reduced diameter guideway defined in a guide element as it is moved into the winding slot.

Abstract: A polyethylene terephthalate film suited for motor insulation is described having the following:(a) an intrinsic viscosity of 0.80;(b) a lateral crystalline size of not greater than 65 Angstroms;(c) an extractable oligomer content of no more than 0.6% by wt.;(d) a hydrolytic lifetime of at least 500 hours;(e) a density within the range from 1.385 to 1.395;(f) no more than 3% by weight comonomer;(g) no more then 1.5% by weight of diethylene glycol as a comonomer;(h) a carboxyl content of no more than 25 milliequivalents per gram of polymer;(i) a particulate content of 0.1 to 2 weight % with the proviso that the polyethylene terephthalate film does not contain an end capping agent; and(j) an embrittlement time at 160.degree. C. of more than 100 days.

Abstract: Electrical insulating compositions of vinyl halide resins (PVC) are formulated to contain a polymeric metal aromatic polycarboxylate as an electrical insulating additive. For example, polymeric calcium terephthalate is used in minor amounts of about 0.2 to 0.5 phr PVC to provide an excellent insulating effect. Lead stabilizers may be avoided in the polymer compositions and, instead, nontoxic metal salt heat stabilizers such as calcium, barium, zinc, etc., may be used.

Abstract: A machine for forming electric motor stator insulating material and inserting it vertically directly into the stator placed on the pallet of a transportation system, without removing the stator from its pallet. The machine includes a guiding system for the paper fed from a feed roll, with the following elements working in sequence: a pair of rollers for trimming the paper to the required width; a pair of paper shaping and pulling rollers, at least one of which is motor-operated and the other of which can be moved away from the first one during insertion of the paper into the machine; a paper cutter operating in a substantially horizontal direction for cutting across the paper; a former for forming the cut paper inside vertical guides and operating parallel to the cutter; and an inserter for inserting the cut and bent paper into the stator slot and operating in a vertical direction moving through the paper former.