Inductors and electromagnets are widely used components in electrical devices such as motors, generators, and transformers. While both components utilize a wire coil to establish a magnetic field, they each have functional differences that influence their suitability for a given application. Here, we highlight their similarities and differences while providing examples of how each is used in various electrical and electromechanical devices.
What are Inductors and Electromagnets?
An inductor is a two-terminal electrical component consisting of a wire wound into a coil. When electricity is applied to the coil, a magnetic field forms and gradually increases in strength. This magnetic field eventually collapses and is converted into electrical energy that is released back into the circuit.
The ability of inductors to temporarily store energy in an electromagnetic field makes them useful for:
- Slowing current surges and spikes in circuits
- Storing and delivering energy to a circuit
- Impedance matching
Inductors are categorized into the following types:
- Coupled inductors featuring two coils connected by electromagnetic induction
- Multi-layer inductors featuring a layered coil wrapped around a core
- Ceramic core inductors featuring a dielectric ceramic core
- Molded inductors created using plastic or ceramic housings
Like inductors, electromagnets consist of a coiled wire through which electricity flows to produce a magnetic field. The strength of the magnetic field is proportional to the number of turns in the coil. To further increase the magnetic field’s strength, the coil is often wound around a ferromagnetic or iron core.
In contrast to permanent magnets, the strength of an electromagnet’s magnetic field can be adjusted by modifying the amount of current flowing through the coil. The magnetic field can also be “turned off” by removing the electricity source from the magnet. This controllability makes electromagnets ideal for everything from powering electric doorbells to lifting and moving large pieces of metal.
Electromagnets include three main types:
- Resistive electromagnets featuring copper wires twisted around an iron core
- Superconducting electromagnets featuring cryogenically cooled coils of superconducting wire
- Hybrid electromagnets featuring a combination of resistive and superconducting electromagnets
Applications of Inductors and Electromagnets
One of the most well-known uses of inductors is in induction motors, where they generate the magnetic field required to rotate the motor’s shaft. The speed of the shaft’s rotation is directly proportional to the frequency of the power supply. Other inductor applications include:
- Filtering/blocking. In electrical circuits, inductors can filter, choke, or block higher-frequency alternating currents and smoothen output voltages.
- Transformers and converters. Inductors transfer and store energy in transformers and power converters.
- Tuning circuits. In tuning circuits, inductors allow a specific frequency to be selected.
- Sensors. Contactless electronic proximity sensors utilize inductors in the head of the sensor to enable inductive sensing.
- Ferrite beads. When used in ferrite beads, inductors help reduce electromagnetic interference in audio circuits.
- Electromagnetic relays. Electromagnetic relays are automatic switches that use electromagnetic induction to open or close the switch during operation.
The power and versatility of electromagnets make them an essential component of everything from small consumer electronics to mass-transit systems. In maglev trains, for example, electromagnets line the undercarriage of the train to levitate it above the guideway. Other applications of electromagnets include:
- Motors and generators
- Electric doorbells and buzzers
- Magnetic locks
- Headphones and speakers
- Induction heating systems used in cooking and manufacturing equipment
- Medical equipment such as MRIs and heart monitors
- Magnetic recording technology and data storage devices such as hard disks and tape recorders
- Laboratory research equipment such as mass spectrometers
- Particle accelerators
- Magnetic separation equipment
- Industrial lifting equipment
Custom Inductors and Electromagnets from Custom Coils
Inductors and electromagnets provide essential functions in a range of electrical systems and electronic devices. At Custom Coils, we design and manufacture custom inductors and electromagnets according to specific field requirements and performance expectations. From high-quality materials to expert design recommendations, our in-house resources and experience allow us to create long-lasting products for nearly any electrical application.
Custom Coils Inc. designs and manufactures custom specialty coils for a variety of industries and applications. For even the most challenging projects, our experts can deliver high-quality design conceptualization, prototype development, testing, and production. This page will explain how electromagnetic coils work, their different types and applications, and important design considerations when creating custom solutions.
What are Electromagnetic Coils?
An electromagnetic coil, also known as an electric coil or inductor, is an electrical conductor containing a set of conductive wires wrapped around a specified shape and size. This can be a self-supporting (air core) design or include a specified core (ie. iron, ferrite) . Electrical coils are simple electronic components that provide inductance in an electromagnetic circuit.
There are many coil types to meet the needs of various equipment. Electromagnetic coils can vary by wire gauge, length, coil diameter, core material, and other factors. Since electromagnetic coils are powered by electricity, they can be turned on and off easily. Their magnetic strength can be altered by increasing or decreasing the electricity that flows around their core.
How Do Electromagnetic Coils Work?
Electromagnetic coils consist of conductive wire wrapped in a specific size and shape, producing a magnetic field. The magnetic field grows stronger when there are more turns of wire on the coil. Electromagnetic field strength is determined by the number of amp turns, the material selection of the core, and the strength of current. Removing electrical input disables the magnet.
When added to a wire coil, certain core materials can increase the strength of the magnetic field. Ferromagnetic materials—cobalt, nickel, iron, and steel—can amplify a denser magnetic field for the coil.
Types of Electromagnetic Coils
Since electromagnetic coils are critical components used in many industrial applications, the coils must meet the varied demands of each one. The following are some of the most common types of electromagnetic coils and how they’re used.
- Automotive electric coils: Ignition coils in automobiles typically consist of two sets of copper wires wrapped around an iron core. The primary winding is a heavy wire, while the secondary wire is smaller and lighter.
- Energy electric coils: These coils must be engineered to withstand harsh environmental conditions in remote locations.
- Electronic electric coils: Made from finely wound wire, coils for electronic devices are in high demand. Circuit board coils go into laminated transformers.
- Electric guitar electric coils: The single coil design is the most popular form of electric guitar coil, but another form is the double coil, which helps cancel out interference.
- Medical electric coils: Coils in medical equipment, such as Radiation Therapy Systems, must be reliable. These typically high power applications require very precise process and testing procedures.
- Military electric coils: Like medical coils, military coils must be accurate and reliable. They must also be able to perform in harsh conditions. These coils are commonly used in guidance systems, sensors, and navigation systems.
- Transportation electric coils: Railroad tracks, armatures, and signaling devices all use these coils, which can withstand the constant vibrations that occur in these environments.
- Wind-powered generator electric coils: These coils must withstand temperatures up to 200 °C. They are made from lightweight materials and insulated for added protection.
- Flowmeter electric coils: Used to measure the volume of liquid or gas going through a pipe, flowmeter coils must match the radius of the pipe.
- Traffic light sensor electric coils: Inductance meters attach to these coils and change when a car enters its field, alerting the traffic light of the car’s presence.
- Transformer electric coils: Transformers utilize multiple coils to conduct electricity, with primary windings on one side and secondary windings on the opposing side.
- Linear Accelerators coils: Electromagnets (Dipole magnets) are used extensively for beam guiding and bending to move charged particles where they need to go.
Electromagnetic Coil Applications
Electromagnetic coils vary in size, shape, and material depending on their application. While there are many industries that use electromagnetic coils, three industries in particular rely on coils for critical applications.
Electromagnetic components are vital to many types of medical equipment, including heart rate monitors, Radiation therapy systems, MRI systems and more. Diagnostic equipment—such as electrocardiogram (EKG) and electroencephalogram (ECG) machines—also require electromagnetic coils.
The military depends on electromagnetic coils for missile defense, protecting allied signals, and jamming enemy signals. Electromagnetic coils also apply to high-velocity electromagnetic rail guns.
Aerospace applications for transformers, inductors, and other electromagnetic parts must be highly precise and adhere to stringent guidelines. Electromagnetic aircraft launch systems, for example, must successfully launch aircraft from carriers.