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　　A thyristor is... Medium-frequency electric furnace The core of the medium-frequency power supply—the proper use of which is crucial to the operation of the equipment—is vital. When using a medium-frequency induction furnace, it’s normal for a few thyristors to occasionally fail. However, if silicon devices frequently burn out, this should raise red flags. Thyristors operate at currents of several thousand amperes and typically handle voltages ranging from one to two thousand volts. Therefore, robust main control board protection and excellent water-cooling conditions are essential.

　　Thyristor Overload Characteristics: Damage to a thyristor is referred to as breakdown. Under normal water-cooling conditions, the thyristor can withstand overcurrents exceeding 110%. However, it has no ability to handle overvoltage—meaning that silicon devices will definitely be damaged if subjected to excessive voltage. To account for surge voltages, manufacturers typically select silicon components with a rated voltage 3 to 4 times higher than the operating voltage when designing equipment. For example, if the rated operating voltage of an intermediate-frequency cabinet is 1750V, two silicon components with a withstand voltage of 2500V each would be connected in series, resulting in an equivalent withstand voltage of 5000V. Intermediate-frequency induction furnace.

　　The correct installation pressure for thyristors is 150–200 kg/cm². When the equipment leaves the factory, it is typically pressed using a hydraulic press. The maximum manual torque achievable with a standard wrench cannot reach this value; therefore, there’s no need to worry about silicon cracking when applying manual pressure. However, if the connection becomes loose, poor heat dissipation could cause the silicon to burn.

　　Thyristor heatsink structure: water-cooling chamber + multiple copper pillars for support. If the circulating water is too hard, scale will build up inside the water chamber, leading to poor heat dissipation. Similarly, if leaves or other debris enter the water chamber, it can also cause flow obstruction.

　　The factory test temperature for thyristors is 100℃ (junction temperature). Under normal circumstances, maintaining the circulating water temperature below 45℃ is sufficient to ensure the proper operation of the electrical cabinet. A handheld infrared thermometer is extremely useful. A thermometer capable of measuring up to 350℃ costs only a few hundred yuan—relatively inexpensive. By using it to measure the temperature of the thyristors and heat sinks in the working power supply, you can promptly detect any abnormal areas and address faults in a timely manner. Medium-frequency induction furnace

　　The surface of the heatsink’s workbench must match the dimensions of the component’s workbench surface to prevent damage to the equipment caused by misalignment and tilting. The heatsink’s workbench surface must have high flatness and smoothness. It is recommended that the roughness of the heatsink’s workbench surface be less than or equal to 1.6 mm, and its flatness be less than or equal to 30 mm. During installation, both the component’s workbench and the heatsink’s workbench should be kept clean and free from any dirt, oil, or other contaminants.

　　During installation, ensure that the silicon component’s surface is perfectly parallel and concentric with the heatsink’s surface. During installation, apply pressure through the component’s centerline to ensure even distribution of force across the entire contact area. When installing manually, it is recommended to use a torque wrench to apply uniform, alternating torque to all fastening nuts; the applied torque should meet the specified requirements.

　　When reusing a water-cooling radiator, pay special attention to checking whether the base surface is smooth and flat, whether the water chamber has scale or blockages, and especially whether the base surface is dented. If any of these conditions are present, the radiator should be replaced.

　　What is the principle behind medium-frequency induction furnace equipment? Medium-frequency electric furnace Principle: Based on the fundamental principle of electromagnetic induction, three-phase power-frequency AC is rectified into DC, and then the DC is converted into an adjustable intermediate-frequency current. This current powers a load consisting of capacitors and induction coils (which can be connected in parallel or in series). As a result, high-density magnetic flux lines are generated within the induction coil and cut through the metallic materials contained therein, inducing large eddy currents in the metal.