Rectifier Circuits Applicable to Medium Frequency Induction Furnace Transformers
Common rectifier circuits include single-phase half-wave, single-phase full-wave, three-phase half-wave, three-phase full-wave (Y or △) bridge, three-phase zigzag (ZO type), six-phase Y-type (center-tapped), six-phase fork-type (double zigzag), six-phase Y-type parallel bridge (with balancing reactor), and six-phase △Y-type series bridge. Also included are twelve-phase four-zigzag type with balancing reactor, six-phase Y-type or other forms, six-phase (twelve, twenty-four phase) double star type with balancing reactor, or multiple sets of parallel bridge and double anti-parallel circuits. The DC current can reach 25KA, and the DC voltage ranges from tens of volts to hundreds of volts. The valve side often uses in-phase inverse parallel connection for output.
(1) Core: Uses 30Q120 high-permeability silicon steel sheets, and employs an advanced 3-6 level step-lap core stacking method, effectively reducing no-load loss, no-load current, and noise.
(2) Windings: High-conductivity oxygen-free copper wire is used for the windings. The windings adopt a new integrated assembly process with cylindrical, double-disc, and new spiral structures, making the product structure more compact and ensuring effective main insulation. The end layers are reinforced to improve insulation performance. High-strength compression tape is wrapped around the outer surface of the windings, increasing the mechanical strength of the windings and significantly improving the product's impact resistance and short-circuit resistance.
(3) Transformer Body: The insulation pads of the transformer body are supported by high-strength laminated wood and laminated cardboard, ensuring that the support area at the ends of the windings reaches more than 95%, further improving the product's short-circuit resistance and operational reliability. The insulation material uses high-strength, high-density cable paper wrapping, with an allowable pressure of 45 MPa. (4) Oil Tank: The oil tank uses heat dissipation oil pipes (double-row and triple-row pipes use finned designs), or a stepped fin radiator, increasing heat dissipation capacity under the same tank wall area; calculations can also be made to install finned radiators or use corrugated oil tanks, as well as forced oil-air cooling or forced oil-water cooling radiators, according to user requirements. Oil tank surface treatment: The transformer casing paint uses a "radiator" type paint (anti-smoke, moisture-proof, and mildew-proof). This paint has strong adhesion to the primer, good decorative properties, a thin film, good corrosion resistance, gloss retention, and color retention, as well as good leveling and covering power.
