Preparation method for resistor sheet used for overvoltage protector of urban rail transit

Abstract

The invention discloses a preparation method for a resistor sheet used for an overvoltage protector of urban rail transit. The preparation method is characterized in that ZnO is used as a main raw material; additives comprise oxides and organic additives like Bi2O3, Co2O3, Cr2O3, Mn3O4, NiO, Sb2O3, Si02, Al(NO3)3 and glass powder; and the preparation method comprises main preparation steps like refining of mixed additives, mixing of the additives and ZnO, spray granulation, sheet pressing, rubber discharging, sintering, heat treatment, aluminum spraying, and coating of an insulating layer. According to the invention, through adjustment of the contents of the oxides of the additives, optimization of a formula like the proportion of the main raw material ZnO, and adjustment of a sintering ceramic-forming process and a heat treatment process, the resistor sheet with good square wave discharge current capacity and excellent aging performance is obtained; meanwhile, the resistor sheet has the advantages of excellent protective characteristics, simple preparation process, low energy consumption, safety and reliability, and fully realizes protection of a traction motor and electrical equipment from being damaged by overvoltage when used in rail transit.

Description

technical field [0001] The invention relates to a method for preparing a resistance sheet for a rail transit voltage protector, and belongs to the technical field of preparation of functional ceramic materials. Background technique [0002] The power supply system of urban rail transit will be attacked by transient overvoltage, operating overvoltage and lightning overvoltage during operation, which will directly damage or continuously deteriorate the insulation of system equipment, thus causing accidents. In the rail transit power supply system, the catenary power supply system used to provide power traction, locomotive power and related electrical equipment is in an important position, and its lightning overvoltage protection is an important guarantee for the safe operation of rail transit. The existing overvoltage protector used for the overvoltage protection of the rail transit catenary is a DC metal oxide protector with a rated voltage of 2.4kV. There are two types of it...

AI Technical Summary

Problems solved by technology

[0003] The formula design of ZnO varistors for DC systems in patent CN102390992B includes Bi, Sb, Cr, Mn, Co, Ni, Zr, Al, B, Zn. There are many kinds of oxides in the formula, and the preparation process includes calcination of additives → material preparation → Granulation→pressing→debinding, pre-firing→firing→grinding→heat treatment→electrode spraying→coating insulation layer, the process cycle is long, in which the additive calcination and pre-firing process increase the production cost and cause a certain amount of energy consumption

[0004] Patent CN200910010647.1 discloses a DC zinc oxide resistance chip that adopts grinding after calcination, bismuth paste coating process and DC diffusion process. This process requires the addition of bismuth oxide slurry preparation equipment and coating equipment, and requires a long diffusion time Bismuth oxide can be uniformly diffused, so the process is complicated, the energy loss is large, and the production cost is high

[0005] In the patent CN102249666A, the resistor chip green body after debinding is placed on a high-temperature-resistant ceramic plate with a double-layer gasket, so that the green body is sealed in the space surrounded by the ceramic plate and the ceramic crucible for primary sintering. Although the process omits the DC coating and DC diffusion process, but the production efficiency is low, and the design of a closed environment with high bismuth content will produce waste of bismuth oxide, which will increase the cost and make the actual operation difficult

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