Strengthened by a partnership with the
Fives Celes company, specialised in the field of induction heating
for over 40 years, BTF commercialises the full range of products needed for induction heating. Using its brand new
laboratory, BTF performs testing directly on the premises on the basis of samples supplied by the client for all types
of applications.
Induction heating equipment usually includes:
The equipment can be adapted according to the applications.
Basic principle of induction heating
Induction heating is the application of two fundamental electrical principles: Lenz’s Law and the Joule effect. An alternating magnetic field is created by a suitable device called an “inductor”; usually a solenoid. According to Lenz’s Law, this field generates, in turn, an electromotive force and thus a varying current in the component to be heated.
Based on the principle of the Joule effect, this induced current heats the part being treated. The inductor is not necessarily a solenoid. In fact, any conductor subjected to an alternating current creates a periodic magnetic field H. It is this field that creates the induced currents in a conducting body positioned nearby.
A whole range of shapes and sizes of conductors can be employed and their specific design needs to be studied in detail according to: the application (melting, uniform heating, heat treatment, welding, brazing,…), the shape of the product (wires, sheets, tubes, bars, fastenings,...).
The induced current (and thus the heat) circulates through the upper zones of the part being treated. It is thus vital to evaluate the depth reached by the currents. This distance is known as the “penetration depth”. Its value depends upon the properties of the material to be heated and to a greater extent on the frequency, as determined by the following law:
The greater the power supply frequency f, the more the current is concentrated at the surface. Low frequencies are thus employed for heating the core of the material while higher frequencies are used, among other reasons, for surface treatment.
Induction heating equipment usually includes:
- A medium or high frequency power supply
- A frequency converter (generator or inverter)
- A panel for adapting impedance and compensation for each bank of capacitors
- A control and operation unit for the installation
- One or more heating inductors
- A cooling system for the power supply, the adaptation panel and possibly the inductor(s)
- A system for orienting and handling the components to be heated
The equipment can be adapted according to the applications.
Basic principle of induction heating
Induction heating is the application of two fundamental electrical principles: Lenz’s Law and the Joule effect. An alternating magnetic field is created by a suitable device called an “inductor”; usually a solenoid. According to Lenz’s Law, this field generates, in turn, an electromotive force and thus a varying current in the component to be heated.
Based on the principle of the Joule effect, this induced current heats the part being treated. The inductor is not necessarily a solenoid. In fact, any conductor subjected to an alternating current creates a periodic magnetic field H. It is this field that creates the induced currents in a conducting body positioned nearby.
A whole range of shapes and sizes of conductors can be employed and their specific design needs to be studied in detail according to: the application (melting, uniform heating, heat treatment, welding, brazing,…), the shape of the product (wires, sheets, tubes, bars, fastenings,...).
The induced current (and thus the heat) circulates through the upper zones of the part being treated. It is thus vital to evaluate the depth reached by the currents. This distance is known as the “penetration depth”. Its value depends upon the properties of the material to be heated and to a greater extent on the frequency, as determined by the following law:
The greater the power supply frequency f, the more the current is concentrated at the surface. Low frequencies are thus employed for heating the core of the material while higher frequencies are used, among other reasons, for surface treatment.
