KBSG Flameproof Dry-Type Transformer for Mine Use

Purpose and Operating Conditions

1.1 This product is used in mines with methane gas mixtures and coal dust where explosion hazards exist, serving as a power distribution device for fully mechanized mining equipment in underground coal mines.

1.2 Operating Conditions: This product operates continuously for long periods under the following conditions and at the rated capacity.

a. Altitude: Not exceeding 2000m;

b. Ambient temperature: Not higher than +40°C;

c. Relative air humidity: Not exceeding 95% (at +25°C);

d. Environment free from severe bumping and vibration, with a vertical inclination not exceeding 15 degrees;

e. Free from gases and vapors sufficient to corrode metals and damage insulation;

f. Location free from dripping water.

Structural Overview

The KBSG flameproof dry-type transformer for mine use consists of a cabinet shell, a cabinet cover, a core assembly, an insulation assembly, high-voltage leads, low-voltage leads, and a trolley for railway tracks, among other components.

The transformer cabinet shell features a flameproof structure with a top-opening cover, and four small lifting lugs are provided on the cabinet cover for hoisting during cover disassembly. Corrugated steel plates are adopted for both sides of the cabinet shell, and thick steel plates for the cabinet bottom. Wiring flanges are installed on both the high and low-voltage sides of the transformer for connecting high and low-voltage switches. Four large lifting lugs are arranged on the cabinet shell for integral hoisting of the transformer; earthing bolts and blue earthing marks are welded at both ends of the cabinet shell for connecting external earthing wires. Inside the transformer, high-low voltage interlock wires and temperature control wires are connected to the high and low-voltage switches respectively; PT100 platinum resistors or temperature relays are used for temperature control, which send an over-temperature signal when the internal temperature of the transformer is excessively high.

The transformer core assembly is composed of an iron core, clamps, insulation parts and other components. The iron core is made of high-quality cold-rolled grain-oriented silicon steel sheets with a multi-step fully mitered three-seam lamination structure to reduce no-load loss and no-load current; the cut edges of the silicon steel sheets are coated with anti-rust fluid, and the surfaces of the core columns and lower yokes are painted with high-temperature resistant, anti-rust and moisture-proof paint. Channel steel is used for the clamps, and a tie rod structure for vertical tensioning; measures are taken to prevent relative displacement between the iron core and clamps to avoid affecting product quality. The core insulation parts are made of high-quality domestic insulation materials.

The transformer insulation assembly includes main and longitudinal insulation, high and low-voltage coils, coil compression and other structures. High-grade insulation materials are adopted for the main and longitudinal insulation; the high and low-voltage coils are manufactured with a tight winding process to enhance the mechanical strength of the coils; C-class insulated paper-wrapped oxygen-free copper conductors are used for the high and low-voltage coils, ensuring an even electric field around the coils and low partial discharge. A pressure pin and porcelain pressure block structure is used for coil compression with anti-loosening measures. High-voltage leads are led out by cables, and low-voltage leads by cables or copper busbars. The creepage distance and air clearance are greater than the relevant provisions in GB3836.3-2000, ensuring no sparks, electric arcs or dangerous temperatures are generated under normal operating conditions for safe and reliable use. The trolley is fixed to the bottom of the cabinet with bolts and is detachable, with a gauge of 900/600mm.