How does a Transformer work - Working Principle electrical engineering

Summary

In this video from TheEngineeringMindset.com, Paul explains the working principles of transformers, focusing on the necessity of alternating current (AC). He demonstrates how a magnetic field is created with electricity and how it induces electromotive force (EMF) in a secondary coil. The video covers the basics of step-up and step-down transformers, highlighting their roles in voltage regulation for power transmission. Paul also introduces three-phase transformers and their configurations. The video is part of an electrical engineering series and encourages viewers to explore additional related content for deeper understanding.

Takeaways

• ⚡ Transformers only work with AC (alternating current) because it creates a changing magnetic field.
• 🔄 Alternating current (AC) alternates direction, which causes a magnetic field to constantly change polarity and intensity.
• 🌀 A basic transformer operates by inducing electromotive force (EMF) in a secondary coil via the magnetic field from a primary coil.
• 🧲 Placing a ferromagnetic core (such as iron) between the coils increases efficiency by directing the magnetic field to the secondary coil.
• 💡 Eddy currents can cause energy loss as heat, which engineers reduce by using laminated iron sheets in the core.
• ⬆️ Step-up transformers increase voltage and decrease current by having more turns in the secondary coil than the primary coil.
• ⬇️ Step-down transformers decrease voltage and increase current by using fewer turns in the secondary coil compared to the primary coil.
• 🏙️ Transformers are essential for transmitting electricity over long distances, stepping up voltage for transmission and stepping it down for local use.
• 🔗 Three-phase transformers can be configured using three separate transformers or built as a single unit with a shared iron core.
• 🔺 One common transformer connection is the Delta-Wye (or Delta-Star) configuration, with the center point of the Wye side grounded for neutral lines.

Q & A

What is the main focus of the video from TheEngineeringMindset.com?

The video focuses on how transformers work, covering topics such as magnetic fields, the role of alternating current (AC) in transformers, and the differences between step-up and step-down transformers.

Why can transformers only work with alternating current (AC) and not direct current (DC)?

Transformers only work with AC because it creates a constantly changing magnetic field, which is necessary to induce electromotive force (EMF) in the secondary coil. DC creates a constant magnetic field, which does not induce EMF.

How is a magnetic field created in a transformer, and how does it induce current in a secondary coil?

A magnetic field is created when alternating current flows through a primary coil, and this field changes in intensity and polarity. The changing magnetic field induces a current in the secondary coil by disturbing the free electrons and forcing them to move, generating electromotive force (EMF).

What is the role of the iron core in a transformer?

The iron core in a transformer helps guide the magnetic field between the primary and secondary coils, increasing efficiency by ensuring that more of the magnetic field is used to induce current in the secondary coil.

What are Eddy currents, and how do they affect transformer efficiency?

Eddy currents are currents that swirl around the iron core, causing it to heat up and leading to energy loss in the form of heat. To reduce this effect, laminated sheets of iron are used in the core to minimize Eddy currents and improve efficiency.

What is the difference between step-up and step-down transformers?

A step-up transformer increases the voltage in the secondary coil and reduces the current, achieved by having more turns in the secondary coil than in the primary coil. A step-down transformer decreases the voltage and increases the current, using fewer turns in the secondary coil than in the primary coil.

Why are step-up transformers used at power stations?

Step-up transformers are used at power stations to increase the voltage and reduce the current for long-distance transmission, which helps reduce energy losses in transmission cables.

What configuration is commonly used in three-phase transformers?

The Delta-Wye (or Delta-Star) configuration is commonly used in three-phase transformers. In this setup, the primary side is wired in a Delta configuration, and the secondary side is wired in a Wye configuration, often with the center point grounded to allow a neutral line.

What is the role of laminated sheets of iron in the core of a transformer?

Laminated sheets of iron are used in the core to reduce Eddy currents, which minimizes heat loss and improves the efficiency of the transformer.

How does the voltage in a secondary coil of a transformer relate to the number of turns in the coil?

The voltage in the secondary coil of a transformer is proportional to the number of turns in the coil. A higher number of turns increases the voltage (step-up transformer), while a lower number of turns decreases the voltage (step-down transformer).