[hamdani yusuf (OP)]

How does induction heater work? This video can provide a starting point for us to understand the device better.

In this video I will show you how a common induction heater works, what kind of materials it can heat up and how you can easily create your own.

I've got a cheap ZVS (zero voltage switch) induction heater to explore its behavior. It has 120W maximum power, and working at 5-12VDC. I've tested its functionality, and I'm planning to investigate further on its characteristics, and how it reacts to different things.

[Bored chemist]

How does induction heater work?

By induction.

[hamdani yusuf (OP)]

How does induction heater work?

By induction.

How do its effectiveness and efficiency change with changes of following parameters?
Working frequency
Working Voltage
Working current
Inductance of the coil
shape of the coil
size of the heated material
shape of the heated material
substance of heated material

[hamdani yusuf (OP)]

I've got a cheap ZVS (zero voltage switch) induction heater to explore its behavior. It has 120W maximum power, and working at 5-12VDC. I've tested its functionality, and I'm planning to investigate further on its characteristics, and how it reacts to different things.

Commercial induction cookers have safety equipment in it, which limits our usage to explore its behaviors in various circumstances. The electronic kit that I use here has no such thing, which is more preferred. But it also poses risk of breaking the components, especially the transistors. I burnt them down previously when the heating coil was disconnected from the circuit.

[hamdani yusuf (OP)]

 

I've got a cheap ZVS (zero voltage switch) induction heater to explore its behavior. It has 120W maximum power, and working at 5-12VDC. I've tested its functionality, and I'm planning to investigate further on its characteristics, and how it reacts to different things.

I've done recording some experiments using the induction heater. I got some interesting results which I'd like to share here. The heated objects are mostly ferrous materials. Different shapes, orientation, and position of object around the heating coil affect the heating power, which is measured using clamp Ampere meter and thermal camera.

[Bored chemist]

How does induction heater work?

By induction.

How do its effectiveness and efficiency change with changes of following parameters?
Working frequency
Working Voltage
Working current
Inductance of the coil
shape of the coil
size of the heated material
shape of the heated material
substance of heated material

In a very complicated way.

[hamdani yusuf (OP)]

https://en.m.wikipedia.org/wiki/Induction_heating
An induction heater consists of an electromagnet and an electronic oscillator that passes a high-frequency alternating current (AC) through the electromagnet. The rapidly alternating magnetic field penetrates the object, generating electric currents inside the conductor, called eddy currents. The eddy currents flow through the resistance of the material, and heat it by Joule heating. In ferromagnetic and ferrimagnetic materials, such as iron, heat also is generated by magnetic hysteresis losses.

A thin steel wire or a needle at the axis of heating coil is unlikely to generate significant eddy current. Most heat would be generated by magnetic hysteresis losses. Is the heating power affected by wire length?

[hamdani yusuf (OP)]

I've got a cheap ZVS (zero voltage switch) induction heater to explore its behavior. It has 120W maximum power, and working at 5-12VDC. I've tested its functionality, and I'm planning to investigate further on its characteristics, and how it reacts to different things.

Commercial induction cookers have safety equipment in it, which limits our usage to explore its behaviors in various circumstances. The electronic kit that I use here has no such thing, which is more preferred. But it also poses risk of breaking the components, especially the transistors. I burnt them down previously when the heating coil was disconnected from the circuit.

Here's my introduction to the mini ZVS induction heater I will use to conduct the experiments.

[hamdani yusuf (OP)]

Here are some videos of experiments I've done investigating the work of induction heater.
The first one investigate the heating profile of the heating circuit itself, and some objects with different shapes.

The second video investigates further with the induction heating of various objects.

[hamdani yusuf (OP)]

This experiment shows induction heating of a steel wire with various shape and orientation.

Compare it with a copper cable.

Axially oriented steel wire generates heat while copper wire doesn't. In this case, the heat is generated by magnetic hysteresis losses instead of eddy current.

https://en.wikipedia.org/wiki/Induction_heating
An induction heater consists of an electromagnet and an electronic oscillator that passes a high-frequency alternating current (AC) through the electromagnet. The rapidly alternating magnetic field penetrates the object, generating electric currents inside the conductor, called eddy currents. The eddy currents flow through the resistance of the material, and heat it by Joule heating. In ferromagnetic and ferrimagnetic materials, such as iron, heat also is generated by magnetic hysteresis losses.

Another notable result is that steel wire coil doesn't generate much heat. This fact should give us a clue to improve our understanding about magnetism.

[hamdani yusuf (OP)]

This experiment shows the induction heating of permanent magnets. It seems that magnetic hysteresis losses are not that significant here.

[Rodneyhhernandez]

An induction heater consists of an electromagnet and an electronic oscillator that passes a high-frequency alternating current (AC) through the electromagnet.

[hamdani yusuf (OP)]

An induction heater consists of an electromagnet and an electronic oscillator that passes a high-frequency alternating current (AC) through the electromagnet.

I did some measurements on the device I used here.

I've got a cheap ZVS (zero voltage switch) induction heater to explore its behavior. It has 120W maximum power, and working at 5-12VDC. I've tested its functionality, and I'm planning to investigate further on its characteristics, and how it reacts to different things.

Commercial induction cookers have safety equipment in it, which limits our usage to explore its behaviors in various circumstances. The electronic kit that I use here has no such thing, which is more preferred. But it also poses risk of breaking the components, especially the transistors. I burnt them down previously when the heating coil was disconnected from the circuit.

Here's my introduction to the mini ZVS induction heater I will use to conduct the experiments.

[hamdani yusuf (OP)]

Demonstration of induction heating steel wire with various cut length.

[hamdani yusuf (OP)]

Demonstration of induction heating short steel wires

[hamdani yusuf (OP)]

Before I continue with my experiments, I want to share a video containing important information to understand about eddy current.

[hamdani yusuf (OP)]

In non-ferrous materials, there's no significant heat is generated by magnetic hysteresis losses. The heat is mainly produced by eddy current.

[hamdani yusuf (OP)]

Here's a video showing induction heating of broad metal plates.
It shows that the field outside of the coil is much weaker than the inside.
We can see how plate thickness affects the difference in power consumptions between when the plate is at the end of heating coil and the middle of the coil. My hypothesis for this, is that the thin plate of cutter knife was already saturated by the magnetic field at the edge of the coil. Stronger magnetic field at the middle doesn't add much to the power consumption.

[hamdani yusuf (OP)]

Here's a video of induction heater involving a ferrite rod.
The first interesting thing we can find is that the insertion of ferrite rod can reduce total power consumption, even though it absorbs some energy and generate heat. To do that, it must have taken the energy from somewhere else, e.g. the energy that was previously spread to the surrounding of the coil.