Why frequency is high in induction heating?

Induction heater units incorporate high frequency generators for non-contact heating of metal using electromagnetic induction. When AC is applied to a coil surrounding the work (metal), a magnetic field is generated by the current flowing in the coil, and induced loss (hysteresis loss) is generated causing a heat.

What frequency does induction heating use?

The recommended frequency range is 1.2 to 10 kHz with an optimal frequency around 2.5 kHz.

How does frequency affect induction heating?

Low frequency induction heating has a deeper skin effect which is more efficient for larger parts. As a rule, heating smaller parts with induction requires higher operating frequencies (often greater than 50 kHz), and larger parts are more efficiently heated with lower operating frequencies.

How is a Royer oscillator used in a heater circuit?

The circuit fundamentally makes use of a Royer oscillator which is marked by simplicity and self-resonant operating principle. The functioning of the circuit could be understood with the following points: When power is switched ON, positive current begins flowing from the two halves of the work coil towards the drains of the mosfets.

How does a high frequency induction heater work?

Water cooling systems are also common in high power induction heaters to remove waste heat from the work coil, its matching network and the power electronics. Finally some control electronics is usually employed to control the intensity of the heating action, and time the heating cycle to ensure consistent results.

Why are 27 capacitors used in Royer heater?

The internal construction of MOSFETs with a higher voltage rating makes them unsuitable for use in a self oscillating circuit like this Royer oscillator. A MMC is made from 27 capacitors to avoid excessive heating in a single capacitor. The capacitors will still heat as massive current flows between the tank and work coil.

How does an induction heater cause eddy current?

An induction heater is a device that uses a high frequency magnetic field to heat up an iron load or any ferromagnetic metal through eddy current. During this process electrons inside iron are unable to move as fast as the frequency, and this gives rise to a reverse current in the metal termed as eddy current.