Induction Coils

An electromotive force is produced in the opposite direction to balance off the change by applying an alternating current to the windings. Induction coils are frequently utilized when low voltage needs to be converted to high voltage in televisions and other electronic devices. For example, a car’s ignition system converts power from the battery by an induction coil. Induction coils are simple devices. A core and insulated wires are twisted around the core to form the device.

An air core or a core consisting of magnetic materials can serve as the core. Insulated wires are winded around the core, and coils are either made using insulated wire or uninsulated wire (such as the so-called silver steel) but with an air gap to ensure the required distance between each wire turn. Turn-by-turn winding of uninsulated wire will result in a short circuit; even with some inductance, it won't provide the necessary inductance.

How an Induction Coil Works

Two coils of insulated wire twisted around a common iron core make up an induction coil (M). The main winding (P), is a single coil with just a few coarse wire turns (tens or hundreds). The secondary winding (S), the other coil, is often made up of up to one million turns of thin wire (up to 40 gauge).

The DC supply current from the battery (B) must be frequently connected and disengaged to continuously operate the coil and produce the variations in the magnetic field required for induction. Induction coils use an interrupter or break (A), a magnetically actuated vibrating arm, to quickly link and break the current flowing into the primary coil. The primary circuit's pair of contacts (K) open and disconnect the primary current when the armature has moved far enough. The magnetic field collapses when the current is cut off, resulting in the spark.

On break, an arc occurs at the interrupter contacts, which has unfavorable consequences: the arc consumes magnetic field energy, lowers output voltage, and wears out the contacts. A quenching capacitor (C) of 0.5 to 15 F is connected across the primary coil to reduce the voltage rise after a break to avoid sparks.

The primary magnetic field is produced when an electric current flows through. Most of the magnetic field from the primary winding couples with the secondary winding because of the shared core. The primary winding acts like an inductor, storing energy in the magnetic field it produces. The magnetic field quickly collapses when the main current is abruptly cut off.

Electromagnetic induction induces a high-voltage pulse across the secondary terminals. The secondary voltage pulse is generally hundreds of volts due to the secondary coil's enormous number of spins. An electric spark can frequently be produced by this voltage when it jumps across the air gap (G) separating the secondary winding’s output terminals. Induction coils were originally known as spark coils for this reason.

Power Losses in Induction Coils

Three main categories of power loss are taken into account while using coils. The first is the power loss experienced in a winding wire's serial resistance. When the current running through the coil has a high amperage and causes power losses, this is the most typical source of power loss in power supply circuits. The coil overheats, and as a result, overheats the gadget.

The second power loss is due to overheating of the coil, which overheats the gadget. In addition to being the most frequent source of damage, high temperatures can also short-circuit the coils and ruin the insulation. The third kind of power loss is caused by a loss of magnetic flux, which might be spread out by mechanical mounting components, air gaps in the coil's core, or careless fabrication during coil production.

Applications of Induction Coils

Wireless charging

The electromagnetic induction theory underlies wireless charging. When an electric current is transmitted through an induction coil, a magnetic field is created; this magnetic field's action causes a second, farther away coil to produce an electric current.

Short-circuit the direct current (voltage)

Since there is no change in DC, the inductor has no effect. However, the inductor opposes changes in the current. Since the voltage across the inductor in a DC system is zero, the di/it is zero, and a short circuit results.

Building filters for frequencies

Line filters, which enhance the power quality of an electrical power system, use induction coils to filter frequencies.

Decreasing or increasing voltage

Transformers employ induction coils to raise or lower the voltage in an electrical power system.

Induction heaters

Eddy current occurs on the rebar surface when a high-frequency electric current is applied to an induction coil, creating an alternating field around the coil. Inducing heat in the rebar is this current.

Amplifier coupling

Many electronic devices require numerous amplifiers and stages of amplification. More amplification stages are added when a single stage cannot deliver the necessary amplification. Impedance coupling employs inductive coils.

Advantages of Induction Coils

• Energy savings
• Localized, constant, and precise heating
• Temperature control
• Improved process efficiency
• Pollution-free, fast, and secure technology
• Possibility of integration into production lines
• Improved working environment
• Best quality and yield/performance

Disadvantages of Inductions Coils

• Both the equipment's cost and the process's cost are very high.
• Wireless charging provides very slow charging.
• Induction heating coil efficiency is typically less than 50%, which is low.

Choosing the Right Induction Coil Supplier

For the most beneficial outcome when purchasing induction coils from an induction coil supplier, it is important to compare several companies using our directory of induction coil suppliers. Each induction coil supplier has a business profile page that highlights their areas of experience and capabilities, along with a contact form to directly communicate with them for more information or request a quote. Review each induction coil company website using our patented website previewer to gain an idea of what each business specializes in. Then, use our simple RFQ form to contact multiple induction coil companies with the same form.