Wuxi Wondery Industry Equipment Co., Ltd

I. Project Background and Equipment Specifications This case study involves a medium frequency induction melting furnace, model WDL-KGPS-1000, with a rated capacity of 1 ton and a maximum capacity of 1.2 tons, designed for aluminum melting applications. The equipment employs medium frequency induction heating and is equipped with a hydraulic tilting system for molten aluminum discharge. The electrical system is configured for a 380V/50Hz three-phase power supply, with a three-phase six-pulse rectifier and a parallel-connected inverter. Compared to the 0.8-ton furnace in the previous case, this equipment features a furnace body designed for a maximum capacity of 1.2 tons, with the power supply rated power increased to 600 kW while maintaining the same output frequency of 1000 Hz. This configuration – with power slightly exceeding the furnace's rated demand – provides a margin for enhanced melting rates. II. KGPS Medium Frequency Power Supply System The power supply system adopts the KGPS thyristor-based medium frequency power supply, with a rated power of 600 kW, a medium frequency output voltage of 1500 volts, and an output frequency of 1000 Hz. The power factor exceeds 0.9, and the startup success rate is 100%. The rectifier section is a three-phase full-controlled bridge, with the control circuit employing an eighth-generation digital circuit board architecture. Core control functions include constant power control, swept-frequency zero-pressure soft start, and dual closed-loop voltage-current feedback. The swept-frequency zero-pressure startup means the system automatically scans from high frequency downward during startup, establishing medium frequency oscillation upon finding the load resonant point – an approach that avoids the sensitivity to load parameter variations inherent in traditional separate-excitation startup methods. The protection system encompasses overcurrent, overvoltage, undercurrent, undervoltage, water loss, and phase-loss conditions. When any protection parameter exceeds the set threshold, the system automatically blocks pulse output and disconnects the main circuit power. The power supply cabinet includes full voltage, current, and power readings along with status indicators. The capacitor cabinet provides medium frequency parallel compensation, reducing reactive power transmission losses on the distribution lines and improving the system power factor. The capacitor bank capacity is matched to the resonant frequency of the induction coil, ensuring operation near the resonant point under rated conditions. III. Induction Coil Design and Magnetic Yoke Shielding The induction coil is the core energy conversion component, constructed from T2 copper with a wall thickness of 5 mm. When energized, the coil generates a 1000 Hz alternating magnetic field that induces eddy currents in the metal charge within the furnace hearth, generating heat. The coil design is based on electromagnetic field principles and verified through dedicated computer software, with the deviation between actual operating power and design power controlled within 5%. Turn-to-turn insulation is processed using advanced insulation techniques, with dedicated clamping technology reducing axial vibration of the coil. The coil inner wall is sprayed with imported high-temperature-resistant insulating materials, and a furnace lining leakage alarm system is installed – when molten aluminum seeps into the coil layer, the alarm system detects it early and signals the condition, preventing furnace breakout incidents. A refractory coating of 10 to 15 mm thickness is applied to the inner surface of the coil. This coating serves two functions: facilitating furnace lining construction and preventing thermal deformation of the lining that would affect service life. The magnetic yokes are of crescent profile construction, laminated from cold-rolled silicon steel sheets and clamped with stainless steel splints. The contact surface between the yoke and the coil outer surface is curved, providing face contact rather than line contact, achieving better clamping efficiency and reduced magnetic flux leakage. The silicon steel sheets are reinforced with dedicated splints rather than through-bolts, maximizing the effective magnetic area and reducing localized heating. The magnetic yokes simultaneously shield magnetic flux leakage, prevent furnace body heating, and support and secure the induction coil. IV. Hydraulic Tilting System Furnace tilting is driven by a hydraulic system with two cylinders arranged on both sides of the furnace body for lifting, with furnace return accomplished by gravity. The hydraulic station is equipped with dual motors and dual pumps – one in service and one on standby, with automatic switching capability. The fuel tank is fully enclosed and welded to prevent hydraulic oil leakage. The tilting angle range is 0 to 95 degrees, with smooth operation without shock or creeping, adjustable speed, and the ability to hold at any position. Tilt operation is controlled via manual valves, suitable for casting processes requiring precise control of molten aluminum pouring volume. V. Furnace Body Structure The furnace shell adopts a steel-frame structure, comprising a fixed mounting base and a tilting furnace body, with the overall frame configuration ensuring rigidity. The hearth diameter-to-height ratio has been optimized through computer analysis – an increased ratio improves the natural power factor and enhances electrical efficiency. The furnace body is designed with a 3000 kg lining capacity for melting 1000 kg of aluminum, meaning the hearth volume has a significant margin relative to the rated capacity, facilitating charging operations and reducing spillage risk. VI. Graphite Crucible and Water Cooling System The crucible is of graphite construction, with a recommended service life of 4 to 6 months, depending on operating conditions including charging method, melting temperature maintenance range, and dross removal frequency. The water-cooled cables are constructed from TU1 multi-strand oxygen-free copper wire, sheathed in high-strength fire-resistant rubber tubing, with cold-formed connectors. The power supply side requires a cooling water flow rate of no less than 12 m³/h, while the furnace body side requires no less than 22 m³/h. The outlet water temperature on the power supply side must not exceed 35°C, and on the furnace body side must not exceed 45°C, with inlet water pressure maintained between 0.15 and 0.35 MPa. The water cooling system is equipped with a closed cooling tower, water tanks, and a control cabinet, forming an independent circulating cooling loop.

I. Project Background and Equipment Specifications This case study involves a medium frequency induction melting furnace, model WDL-KGPS-800, with a rated capacity of 0.8 tons and a maximum capacity of 0.96 tons, designed for aluminum melting applications. The equipment employs medium frequency induction heating and is equipped with a hydraulic tilting system for molten aluminum discharge. The electrical system is configured for a 380V/50Hz three-phase power supply, with a three-phase six-pulse rectifier and a parallel-connected inverter. The core technical features of this equipment lie in the combination of the KGPS medium frequency power supply system and the steel-shell hydraulic tilting furnace body, representing a mid-capacity induction melting solution suitable for foundry shop operations. II. KGPS Medium Frequency Power Supply System The power supply system adopts the KGPS thyristor-based medium frequency power supply, which has matured through over a decade of continuous technological development. The rectifier section is a three-phase full-controlled bridge, with a medium frequency output voltage of 1500 volts, rated power of 500 kW, and an output frequency of 1000 Hz. The power factor exceeds 0.9, and the startup success rate is 100%, meaning medium frequency oscillation can be reliably established on every startup attempt. The control circuit employs an eighth-generation digital circuit board architecture, featuring constant power control, swept-frequency zero-pressure soft start, and dual closed-loop voltage-current feedback. The protection system encompasses overcurrent, overvoltage, undercurrent, undervoltage, water loss, and phase-loss conditions. When any parameter exceeds the set threshold, the system automatically blocks pulse output and disconnects the main circuit power. The power supply cabinet and capacitor cabinet are arranged separately. The capacitor cabinet provides medium frequency parallel compensation, improving system power factor and reducing reactive power transmission losses on the distribution lines. The capacitor bank capacity is matched to the resonant frequency of the induction coil, ensuring operation near the resonant point under rated conditions for optimal power output efficiency. III. Induction Coil Design and Magnetic Yoke Shielding The induction coil is the core energy conversion component of the medium frequency furnace. When energized, the coil generates a strong alternating magnetic field that induces eddy currents in the metal charge within the furnace hearth, generating heat. The coil material is T2 copper with a wall thickness of 5 mm, constructed as a spiral tube. The coil design is based on finite element electromagnetic field analysis, with the deviation between actual operating power and design power controlled within 5%. The coil employs advanced turn-to-turn insulation processing, with dedicated clamping technology to reduce axial vibration. The coil inner wall is coated with imported high-temperature-resistant insulating materials, and a furnace lining leakage alarm system is installed to detect molten aluminum seepage risks. A refractory coating of 10 to 15 mm thickness is applied to the inner surface of the coil, serving two functions: facilitating furnace lining construction and preventing thermal deformation of the lining that would affect service life. The magnetic yokes are of crescent profile construction, laminated from cold-rolled silicon steel sheets and clamped with stainless steel splints. The contact surface between the yoke and the coil outer surface is curved, providing face contact rather than line contact, achieving better clamping efficiency and reduced magnetic flux leakage. The silicon steel sheets are reinforced with dedicated splints rather than through-bolts, maximizing the effective magnetic area of the sheets and reducing localized heating. The magnetic yokes serve to shield magnetic flux leakage, prevent furnace body heating, support and secure the induction coil, and improve overall system efficiency. IV. Hydraulic Tilting System Furnace tilting is driven by a hydraulic system with two cylinders arranged on both sides of the furnace body for lifting. Furnace return is accomplished by gravity. The hydraulic station is equipped with dual motors and dual pumps – one in service and one on standby, with automatic switching capability. The fuel tank is fully enclosed and welded, with no openings except for the side and tubing ports, to prevent hydraulic oil leakage. The hydraulic tilting console uses manual valve operation, with a tilting angle range of 0 to 95 degrees. Operation is smooth without shock or creeping, with adjustable speed and the ability to hold at any position. This design is suitable for casting applications requiring precise control of molten aluminum pouring volume. V. Furnace Body Structure The furnace shell adopts a steel-frame structure, comprising a fixed mounting base and a tilting furnace body, with the overall frame configuration ensuring rigidity. The hearth diameter-to-height ratio has been optimized through computer analysis, adopting advanced international furnace profile design principles – an increased ratio improves the natural power factor and enhances electrical efficiency. An enclosed dust collection hood is installed above the furnace upper section to capture fumes and particulates generated during melting. VI. Graphite Crucible and Water-Cooled Cables The crucible is of graphite construction, offering good chemical compatibility with aluminum melting. The crucible service life indicated in the proposal is 4 to 6 months, depending on operating conditions including charging method, melting temperature, and dross removal practices. The water-cooled cables are constructed from TU1 multi-strand oxygen-free copper wire, sheathed in high-strength fire-resistant rubber tubing, with cold-formed connectors providing good electrical conductivity and tensile strength. The power supply side requires a cooling water flow rate of no less than 12 m³/h, while the furnace body side requires no less than 20 m³/h. The outlet water temperature on the power supply side must not exceed 35°C, and on the furnace body side must not exceed 45°C, with inlet water pressure maintained between 0.15 and 0.35 MPa. The water cooling system is equipped with a closed cooling tower, water tanks, and a control cabinet, forming an independent circulating cooling loop. VII. Process Performance Parameters Rated capacity is 0.8 tons, with a maximum capacity of 0.96 tons, and a rated tapping temperature set at 780°C. Melting time is approximately 60 minutes per furnace, with a permissible deviation of ±5%. Based on this, the cycle from cold charging to reaching tapping temperature is approximately 1 hour, corresponding to a melting rate of approximately 0.8 tons per hour. With a rated power of 500 kW, the specific energy consumption is approximately 625 kWh per ton of aluminum, falling within the typical efficiency range for medium frequency induction melting furnaces.

I. Project Background and Equipment Specifications This case study involves an electric resistance tilting aluminum melting furnace destined for the Yemen market, model WDL-GRQ-1500. The equipment is designed for melting non-ferrous metals and alloys with low melting points, with aluminum alloys as the typical processing material. The furnace has a rated capacity of 1,500 kilograms and adopts electric resistance heating, equipped with a hydraulic tilting system for molten aluminum discharge. The electrical system is configured for a 380V/50Hz three-phase power supply, with control power at 220V/50Hz, using a three-phase five-wire connection. The buyer is required to provide a stable power supply with voltage fluctuation within ±10% and frequency fluctuation not exceeding ±3 Hz. This grid compatibility condition requires verification against the local industrial power supply situation in Yemen prior to installation. II. Furnace Structure and Refractory Configuration The furnace shell is constructed from steel plates and sectional steel welded into a cylindrical structure, with continuous full-penetration welds at all joining areas to ensure shell integrity. The lining is divided into two functionally distinct zones: side wall and furnace bottom. The side wall lining employs a composite structure: the innermost layer consists of aluminum silicate fiber modules as insulation, with the working layer constructed from superlight refractory bricks with a density of 0.6 g/cm³. Vermiculite powder is filled into the brick joints and backing to reduce thermal conductivity. The heating elements, made of OCr27A17MO2 high-resistance alloy wire, are embedded within the side wall and controlled as a single zone – meaning the entire furnace chamber uses only one temperature control zone, suitable for scenarios where extreme temperature uniformity is not required but simplified control is preferred. The furnace bottom is constructed from once-forming castable material. Compared to brick-laid bottoms, the monolithic cast structure offers longer service life in terms of resistance to aluminum penetration and thermal shock. An emergency drain hole is designed at the bottom of the side wall to enable emergency emptying in case of aluminum leakage, serving as a safety redundancy feature for melting furnaces. III. Graphite Crucible and Heating System The crucible is a Morgan brand graphite crucible, which holds strong market recognition in the non-ferrous metal melting sector. The crucible service life indicated in the proposal is 6 months or more, depending on actual operating conditions including charging method, melting temperature maintenance range, and dross removal frequency. The heating system core element is OCr27A17MO2 resistance wire, an iron-chromium-aluminum series electric heating alloy with high resistivity and good oxidation resistance. Under single-zone control mode, the rated heating power is 200 kW, connected in star configuration with a working voltage of 380 volts. The maximum furnace temperature is designed at 850°C, with a normal working temperature range of 0 to 800°C. The empty furnace heat-up time does not exceed 3 hours, representing the time window from ambient temperature to the upper working temperature limit. Temperature stability is specified at ±3°C, achieved by the PID regulation system under standard operating conditions. IV. Electrical Control System Configuration The control cabinet uses thyristors (SCRs) as the primary control elements, regulating output current by adjusting the conduction angle. The system employs an advanced phase-shift firing control circuit for continuous and smooth power regulation, rather than simple on-off control. The temperature control system is equipped with two thermocouples: one for measuring the hearth atmosphere temperature and one for measuring the molten aluminum temperature. The thermocouple used for molten aluminum measurement is fitted with a silicon carbide protection tube to prevent chemical corrosion and physical erosion by the molten aluminum. Signals from both thermocouples are fed into two Taiwan-origin temperature controllers, one of which provides PID regulation functionality. The control system incorporates multiple protection logics: when the furnace temperature exceeds the set upper limit or current anomalies occur due to faults, the controller automatically stops pulse output and cuts off power supply. The system also includes a soft-start function with a start delay of approximately 0.5 seconds, designed to reduce inrush current impact on both the power grid and heating elements during cold starts. Low-voltage electrical components include air circuit breakers, contactors, and relays, sourced from CHINT or Omron as industrial-grade standard configurations. V. Hydraulic Tilting System The discharge method is hydraulic tilting, as opposed to a fixed furnace with manual scooping. The hydraulic system drives the furnace body to tilt around its pivot axis, enabling controlled quantitative pouring of molten aluminum from the furnace mouth. This design is suitable for scenarios where molten aluminum needs to be directly transferred to ladles or casting cavities, offering higher discharge repeatability and operational safety compared to manual scooping. The hydraulic system comprises a hydraulic power unit, cylinders, control valve groups, and piping, interlocked with the electrical control system. Tilt angle and speed can be set via the control panel. VI. Process Performance Parameters Summary Rated capacity is 1,500 kilograms, with a melting rate of approximately 450 to 500 kilograms per hour – representing the average aluminum output rate from cold charging to reaching working temperature and casting readiness. With a heating power of 200 kW, the specific energy consumption is approximately 0.4 to 0.44 kWh per kilogram of aluminum, falling within the typical efficiency range for resistance-heated crucible furnaces.