Rotary machine coil, method for manufacturing same, and rotary machine

A rotary machine coil comprising:

• a coil conductor;
• an insulation layer including
• a mica tape which is wrapped around an outer periphery of the coil conductor and in which scale-shaped mica grains overlaid in a thickness direction and a film layer are laminated in this order from the coil conductor side, and
• a cured material of a thermosetting resin composition with which the scale-shaped mica grains overlaid in the thickness direction are impregnated;
• and
• a nano filler included in the cured material and having a higher permittivity than the cured material, wherein
• a permittivity on an inner-layer side of a mica layer in which the scale-shaped mica grains overlaid in the thickness direction are impregnated with the cured material is higher than a permittivity on an outer-layer side of the mica layer,
• the mica grains on the inner-layer side of the mica layer and the mica grains on the outer-layer side of the mica layer are made of the same material, and
• the nano filler is present biasedly on the inner-layer side and the outer-layer side of the mica layer, the nano filler has a higher density on the inner-layer side than on the outer-layer side, the nano filler includes a first nano filler having a great particle size and a second nano filler having a smaller particle size than the first nano filler, and the second nano filler has a lower density on the outer-layer side than on the inner-layer side.

A method for manufacturing a rotary machine coil, comprising the steps of:

• wrapping a fiber layer around an outer periphery of a coil conductor;
• wrapping, around an outer periphery of the fiber layer, a mica tape in which scale-shaped mica grains overlaid in a thickness direction and a film layer are laminated in this order from the coil conductor side;
• impregnating the scale-shaped mica grains overlaid in the thickness direction with a thermosetting resin composition in a liquid state including a nano filler having a higher permittivity than the thermosetting resin composition, from an end of the fiber layer through the fiber layer;
• and
• heating and curing the thermosetting resin composition, wherein
• the mica grains on an inner-layer side of a mica layer in which the scale-shaped mica grains overlaid in the thickness direction are impregnated with the thermosetting resin composition, and the mica grains on an outer-layer side of the mica layer, are made of the same material, and
• the nano filler includes a first nano filler having a great particle size and a second nano filler having a smaller particle size than the first nano filler, and the second nano filler has a lower density on the outer-layer side than on the inner-layer side.