Principle of electromagnetic heater:
An electromagnetic heater is a device that converts electrical energy into heat using the principle of electromagnetic induction. The electromagnetic controller converts 220V/380V, 50/60Hz AC power into DC through rectification circuits, then transforms the DC into a high-frequency current of 10-40kHz via the control circuit. The current flowing through the coil generates a variable alternating magnetic field. When the alternating magnetic flux lines within this field pass through magnetic materials (such as iron, cobalt, or nickel), numerous tiny eddy currents are induced within the metal, causing the metal to self-heating at high speed, thereby achieving the purpose of heating the metal material.
Inverters are the core components of high-frequency electromagnetic heaters, functioning as control devices that convert power supply from industrial frequency (IF) to another frequency using power semiconductor devices. The inverters currently in use predominantly operate in AC-DC-AC mode. They first convert the IF AC power supply into DC power via a rectifier, and then transform the DC power into AC power with controllable frequency and voltage for the motor. The circuit of an inverter typically consists of four parts: rectification, a middle DC section, inversion, and control. The rectification section features a three-phase bridge uncontrolled rectifier, the inversion section is a three-phase bridge IGBT inverter with PWM output, and the middle DC section is responsible for filtering, DC energy storage, and buffering reactive power.
Electromagnetic heating advantages:
Energy-saving, precise temperature control, long lifespan, improved working environment, safe and reliable. Utilizes internal heat heating method, where the heating body's molecules directly感应 magnetic energy to generate heat, resulting in very fast heat-up and an average preheating time reduced by over 60% compared to other heating methods. The thermal efficiency reaches over 97%, and energy saving is up to 30%-70% under the same conditions. The electromagnetic heating coil section uses a ring cable structure, with the cable itself not generating heat, resulting in minimal thermal resistance and low thermal inertia. The outer wall temperature of the heating body is consistent, with real-time and accurate temperature control, and can withstand temperatures above 500°C, with a lifespan of up to 10 years. The surface temperature of the equipment can be improved to a level where it is safe for human touch, enhancing the working environment of the production site and significantly increasing the enthusiasm of production workers, while reducing ventilation and cooling costs during summer. The electromagnetic coil has excellent insulation properties, eliminating the need for direct contact with the outer wall of the heating body, making the heating process safer.
