Abstract: The present disclosure relates to a magnetic circuit of a loudspeaker and a loudspeaker, which can improve the non-linearity of magnetic permeability, thereby reducing the distortion of the loudspeaker. A magnetic circuit comprises a T-yoke with a base and a columnar portion protruding upward from the base, a magnetic steel arranged on the base, and a front sheet arranged on the magnetic steel, wherein the magnetic steel and the front sheet are arranged around a periphery of the columnar portion, and a short-circuit ring is arranged on an inner side of the magnetic steel and/or the front sheet. A first short-circuit ring is provided between the inner wall of the magnetic steel and the outer wall of the columnar portion, and a second short-circuit ring is provided on the inner wall of the front sheet.

Abstract: An anti-pollution-flashover locomotive roof composite insulator, comprising: a support body, and several groups of sheds arranged side by side along the axial direction that are set around the sidewall of the support body, wherein the sheds protrude out of the sidewall of the support body along the radial direction, the upper end of the uppermost shed is set with an upper metal fitting, and the lower end of the lowermost shed is set with a lower metal fitting. The creepage distance of the sheds between the upper metal fitting and the lower metal fitting is 1085 mm-1095 mm, and the arcing distance between the upper metal fitting and the lower metal fitting is 245 mm-255 mm.

Abstract: An interface breakdown-proof locomotive roof composite insulator. The composite insulator comprises: a support body; and at least five shed groups arranged side by side along the axial direction that are provided around the sidewall of the support body, the at least five shed groups includes: at least four shed groups located on the upper end with each group including a large shed and a small shed; and at least one shed group located on the undermost end with each group including two small sheds. For such a shed structure, it is favorable to tolerate impulse voltage, and it is difficult for the interface to be broken down; the electric field on the interface even does not exceed 3 kV/mm, and even if a gas exists on the interface, it will not break through the interface.

Abstract: An anti-pollution-flashover locomotive roof composite insulator, comprising: a support body, and several groups of sheds arranged side by side along the axial direction that are set around the sidewall of the support body, wherein the sheds protrude out of the sidewall of the support body along the radial direction, the upper end of the uppermost shed is set with an upper metal fitting, and the lower end of the lowermost shed is set with a lower metal fitting. The creepage distance of the sheds between the upper metal fitting and the lower metal fitting is 1085 mm-1095 mm, and the arcing distance between the upper metal fitting and the lower metal fitting is 245 mm-255 mm.

Abstract: An interface breakdown-proof locomotive roof composite insulator. The composite insulator comprises: a support body; and at least five shed groups arranged side by side along the axial direction that are provided around the sidewall of the support body, the at least five shed groups includes: at least four shed groups located on the upper end with each group including a large shed and a small shed; and at least one shed group located on the undermost end with each group including two small sheds. For such a shed structure, it is favorable to tolerate impulse voltage, and it is difficult for the interface to be broken down; the electric field on the interface even does not exceed 3 kV/mm, and even if a gas exists on the interface, it will not break through the interface.