Why Transformers Aren't Used in DC Power Supply?
Transformers are a crucial part of the electrical world. They help us transfer electricity efficiently from one place to another, and they’re especially common in the world of AC (Alternating Current) power supply. But have you ever wondered why transformers aren’t used with DC (Direct Current) power supply? In this blog post, we’ll explore the reasons behind this, keeping things simple and easy to understand.
Understanding Transformers
Before we dive into why transformers aren’t used with DC power supply, let’s first understand what transformers do in AC power systems. Transformers consist of two coils of wire known as the primary and secondary coils, wound around a core usually made of iron. When AC electricity flows through the primary coil, it creates a constantly changing magnetic field. This changing magnetic field, in turn, induces a voltage in the secondary coil. This is the magic of transformers – they allow us to change the voltage of electricity easily.
Why do Transformers Love AC?
The Changing Magnetic Field: Transformers work because of the changing magnetic field created by AC electricity. In DC supply, the current flows in only one direction, which means the magnetic field remains constant. Without a changing magnetic field, transformers can’t do their job.
Induction Principle: Transformers rely on electromagnetic induction, which is all about the interaction between a changing magnetic field and a conductor (like a coil of wire). With AC, this change happens naturally, but in DC, it doesn’t. So, the very principle of transformer operation doesn’t apply to DC supply.
Efficiency: AC transformers are highly efficient because they work with the changing magnetic field. DC transformers, if they were possible, would be less efficient due to the constant magnetic field, resulting in energy loss.
Size and Design: To use a transformer with DC, you’d need a specialized design, which would be more complex and bulkier than AC transformers. This makes them impractical for most applications.
Frequency Matters: Transformers also depend on the frequency of the AC supply. In DC, there’s no frequency as the current is steady. This further complicates the use of transformers with DC.
Conclusion
In summary, transformers are amazing devices that make it easy to change the voltage of electricity, but they are built to work with AC power supply due to the nature of electromagnetic induction and the changing magnetic field. DC power supply doesn’t provide the conditions necessary for transformers to function efficiently, which is why they aren’t used with DC. So, the next time you wonder why transformers are absent in DC systems, remember the importance of a changing magnetic field and the science behind these electrical wonders.
Important – In actual practice, those electrical AC devices which act as the source (such as alternator, transformer) always rated in kVA to make their operation independent of the load power factor while the electrical devices which act as the load (e.g., motors) always rated in kW and draw the current from the source according to their power factor.