Method for preparing epoxy resin for casting dry type transformer

Abstract

The invention provides a method for preparing epoxy resin for casting a dry type transformer. The epoxy resin casting material comprises epoxy resin, a curing agent, a toughening agent, packing, a flame retardant and color paste. The casting process comprises the following steps: I, drying the raw materials, putting the epoxy resin combined materials into a heating furnace for heating for 4-5 hours, and adjusting the furnace temperature to be 75 DEG C; II, mixing, namely, mixing the dried raw materials in sequence 30-35 minutes ago before casting; III, when a material tank is heated to be 70 DEG C, starting a material tank vacuum pump to suck the epoxy resin mixed materials into the material tank, and degassing for 20 minutes; IV, casting, and performing curing formation. The preparation method provided by the invention is simple, the flame retardnacy property of the transformer is relatively greatly improved, the impact resistance of the transformer is relatively good, and the epoxy resin can be applied to places with relatively high flame retardancy requirements.

Description

technical field [0001] The invention relates to the field of dry-type transformer preparation, in particular to a preparation method of epoxy resin cast dry-type transformer. Background technique [0002] Casting epoxy resin dry-type transformers have been widely used in urban high-rise buildings and power stations due to their characteristics of flame retardant, safety, reliable operation, convenient maintenance, and small size. In recent years, the production of dry-type transformers in my country has With great development, the number of manufacturers has increased from seven or eight in the 1990s to a hundred. Most of the windings of epoxy resin cast dry-type transformers are casted with epoxy resin, and the intrinsic performance of the formed windings is also improved. Then it is determined that once the performance of the winding after forming does not meet the specified standard, it can only be scrapped. Therefore, in order to ensure the quality of the winding, it is ne...

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Problems solved by technology

[0003] And it is easy to produce bubbles, cracks, deformation, etc. when pouring with epoxy resin, and it is easy to show that the strength of the part is not enough, the electrical properties cannot meet the requirements, the partial discharge is high or breakdown, so the requirements for the casting process are relatively high

[0004] After searching the prior art, Chinese invention patent 200910042044.X provides an epoxy resin composition for transformers and a process for casting transformers with the composition, which includes the following steps: A, epoxy resin, curing agent, Tougheners and accelerators are pre-baked at 65-75°C for 1.5-2.5 hours, and coils are pre-baked at 95-105°C for 8.5-9.5 hours; B. Put the pre-baked mold into the pouring tank after inspection, and start Pouring equipment, then preheat the mixer at 55-65°C in advance, and preheat the pouring tank at 65-75°C; C, feed materials, formula by weight: 100 parts of epoxy resin, 100 parts of curing agent, ~10 parts and 0~0.05 parts of accelerator are put into the mixing tank for mixing; D. Slowly pour the mixture into the mold under continuous vacuum state; E. After the pouring is completed, vacuumize for 0.5~1.5 hours Then start to inflate, and then start vacuuming for 0.5-1.5 hours until the vacuum degree is below 150Pa, and finally come out of the furnace; F, the cast coil is pre-cured; G, clean the mixing tank and pipeline valve with a toughening agent, and clean the Put the material into the mixing tank and stir for 30-40 minutes, but this process does not include the degassing step of the castable, which may generate air bubbles, which will affect the subsequent use of the transformer

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