- High-Frequency Magnetic Components: These components became more prevalent with the advent of high-efficiency switched-mode power supplies (SMPS). Initially, frequencies were around 16kHz, which is just above the human ear range; now, they’re in MHz. High-frequency power supplies are usually used to charge mobile devices. They’re also relied on for switching and regulating computers, electric vehicles, LEDs, TVs, and various communications equipment. Their components are usually made of powdered iron material or ferrite in the core. These cores come in many shapes: the higher the frequency, the smaller the inductor. Multi-strand wire or foil in the insulated tape is used with them. The primary winding is often split into two, which improves magnetic coupling. The triple-insulated wire is common to ensure superior performance in Hi-pot tests. Automated machinery can be used to wind wire onto bobbins; however, manual assembly is necessary for adding insulated tape between windings, adding sleeves to flying leads for fitting cores, protecting safety barriers, and removing wire coating for terminations.
- Low-Frequency Magnetic Components: They’re usually classified as 50 or 500Hz and connect to 220 to 240V AC single-phase mains input in Europe and 115V AC mains input in the US. There are many low-frequency applications, such as conveyor systems, electricity metering, HVAC equipment, line filtering, linear power supplies, motor drives, pumping, and uninterruptible power supplies (UPS). Low-frequency magnetics are usually made of iron or steel laminations in the core material. Often in I or E shapes, they’re interleaved around the winding and bobbin. Toroidal cores, which are grain-oriented silicon iron that winds in a donut shape, can also be used with insulation and wire wound around it. Producing these is more time-intensive, but the core shape means the transformers have low stray magnetic fields and are more efficient and smaller in size.
- Isolated Magnetic Components: This type of component is vital when humans contact electrical output, such as a laptop charger. Transformers help prevent electric shock to the user since the primary circuitry is separated from the secondary circuitry by the transformer. The transformer windings have layers of insulation made of plastic bobbin or insulation tape. Isolated magnetics are also incredibly important to medical technologies. These barriers are typically triple-insulated or use a spacing of several millimeters; sometimes, the barriers use both. Electronics may come in direct contact with patients or users. In these cases, toroidal isolation transformers are used, which ensure that operation isn’t only effective but safe.
- Non-Isolated Magnetic Components: These components are made up of conductors that reduce electronic noise or store energy for short periods. Filters and transformers let them step up or step down AC voltages. For example, a step-down transformer can take a 400V AC/415V AC input to 230V AC.
Designing Custom Magnetic Components for Electronics
Electronic devices are becoming more complex, and few people know more than the barest details about the components they use. Many resources discuss microprocessors, semiconductors, and transistors; however, few explain the functions of the magnetic components vital to these devices. Inductors, transformers, and other components are often considered much lower-tech than other ones. Despite their obscure status, these components are advanced in construction and design. Magnetic elements typically share many design traits, like a foil or wire that’s wound onto a bobbin, core, or mandrel. They can have or lack layers of insulation. Simpler components can occur from automation in high volumes. But, most inductors and transformers are complex and need significant labor. Many magnetic components are custom-designed to fit unique physical and electrical specifications because different applications need distinct parts to be safe and effective. Some inductors and transformers are subject to special safety certifications dependent on their application. Transformer designs always incorporate safe margins. Engineers should be equipped to process acceptance tests and simulate transformers under operating conditions. To ensure that the component won’t overheat during actual use or in the case of short circuits on windings, the client will need to agree to specific type tests, like surge tests. The operating temperature will determine the insulation class used in the component. Typical temperature ratings include B (130°C), F (155°C), and H (180°C). Ambient temperatures also factor into insulation types. Types of Industrial Magnetic Components