Learn about the features and potential configurations of transformers beyond step-up and step-down including core medium, winding arrangement and potential uses.
Transformer Types and Applications
From their earliest designs in 1836, transformers are one of electrical engineering’s oldest developments. They use the principle of electromagnetic induction to convert voltages between a pair of circuits without the need for a physical connection between those circuits. Applications for this principle, however, go beyond the basic “step-up” and “step-down” transformers you’ll see distributing electricity.
We categorize transformers based on the functions they serve. In their most basic application, transformers change voltage levels, so we classify them by whether they increase voltage (step-up), or decrease it (step-down). Other categories include core medium, winding arrangement, configuration, and intended use.
Transformer Cores: Iron and Air
Transformer cores use two main media: iron and air. In air-core transformers, the windings sit on a non-magnetic medium and induction linkage occurs through the air. These transformers are less efficient regarding mutual inductance, but they eliminate hysteresis and eddy current losses. Iron cores, on the other hand, build the windings on a ring made of thin iron plates clamped together to provide better flux linkage and increased efficiency.
Transformer Winding Arrangement
Most transformers consist of a pair of windings. However, a specific kind of transformer, called an autotransformer, uses a single winding that is tapped on one side to provide either step-up or step-down ability. Autotransformers offer greater efficiency since the single winding automatically connects both magnetically and electrically. On the other hand, because of the direct connection between the high-voltage input and low-voltage output, many consider autotransformers unsafe for use in standard distribution circuits.
Transformer Configuration Possibilities
Based on the phase of the system in question, transformers may have many different configurations. Single-phase transformers often power common residential utilities and have either series or parallel configurations.
Here’s one critical distinction between “three-phase power systems” and “three-phase transformers.” Three-phase power systems consist of a three-phase circuit with three single-phase transformers, while three-phase transformers consist of six windings in three pairs. Three-phase configurations require considerably fewer resources to build, making them a more economical choice for transferring large amounts of three-phase power.
Delta-wye transformers refer to the configuration of the three-phase system. These transformers apply to both three-phase power and three-phase transformers. In a delta connection, the circuits connect in a triangle shape (like the Greek letter delta), while in a wye connection, the conductors radiate from a shared center point (like the Greek letter wye).
What is a Transformer Used For? Intended Transformer Use
We categorize some types of transformers by their function:
- Isolation transformers, for instance, use a 1:1 ratio and do not modify the voltage at all. Instead, they isolate a grounded conductor from the circuit load.
- Measurement transformers allow monitoring of high-power systems.
- Instrument transformers are very precise step-down transformers used to allow instruments to read large currents without needing to pass the full power load through the instrument.
- Another kind of precision step-down transformer, called a potential transformer, allows a standard voltmeter to read voltage on the high side of the transformer.
We may categorize transformers into step-up and step-down categories based on their effect on voltage, but we can classify them further according to their practical functions. Whatever their applications may be, transformers are fundamental to our modern system of energy distribution.