# Transformer Questions And Answers

The following information will answer some of the most common questions about transformers, including the various types, their applications and their construction. Transformers allow the transformation of current and voltage to different levels.

One of the fundamentals of transformers is that the current and voltage are always related. For instance, if the voltage is stepped up, the current is stepped down. Transformers do not create power. They simply transform it, as the name implies.

## What Are the Essential Parts of a Transformer?

The essential parts of a transformer are the two coils found in the inside of the device. These are termed the primary and secondary windings. The coils in transformers can be very small, such as those found in the adapters used to connect electrical appliances to wall sockets or can actually weigh in the tons, such as is the case with the transformers used at substations and power stations.

Some transformers are designed with sophisticated cooling systems. These are usually used in high-voltage applications, such as in power lines. The cylindrical devices you see on the sides of power poles are transformers, used to step line voltage down to household voltages.

## What Is the Primary Impedance of a Transformer?

Electrical impedance is the measure of the opposition that a circuit presents to the passage of a current when a voltage is applied. The primary impedance is the impedance of the primary coil on the transformer.

## What Is the Power Factor of a Transformer?

The power factor in electrical systems is expressed as a number between -1 and 1. The power factor measures the capacity of an electrical system to perform work over a specified period of time.

## What Is an Ideal Transformer?

In any electrical system, there are always inefficiencies. An ideal transformer is an imaginary system that does not have any loss. The loss in a transformer is caused when the flux does not make it through the core of the transformer and is absorbed by the insulation. This lost flux is referred to leakage flux. In an ideal transformer, there is also no impedance in the coils. In real life applications, however, there is always some degree of impedance in the transformer’s coils.

## What Are the Two basic Types of Transformers?

There are several different types of transformers in use, but there are two basic types under which they can be classified. Step up transformers take an input voltage and step it up when the voltage is output. Step down transformers take an input voltage and step it down in the output. Step down transformers are commonly used in applications involving household appliances when the appliance needs a lower voltage load than what the wall socket provides to be properly powered. They are also used in computer power supplies, where they step 120V wall voltage down to the 5V and 12V requirements of computer motherboards.

Transformers also come in three-phase designs and others, though the two most basic types are those that are used to increase or decrease the voltage in a circuit.

## Why Does Frequency Remain Consistent During Transformation of Electrical Energy in a Transformer?

Transformers function on AC power. The power supply itself determines the frequency that the transformer operates at and the transformer itself cannot change that. In order to accommodate higher frequencies, transformers need to have less iron in their cores. For lower frequencies, more iron is required. This makes it impossible for a transformer to affect the input or output frequency.

## What Is the Voltage Ratio of a Transformer?

The ratio of the voltages in a transformer is measured by comparing the voltage of the primary coil to the voltage of the secondary coil. The voltage ratio is determined by the number of windings on the coil and is directly proportional to that number. The voltage can be changed in variable transformers, usually by rotating a switch, such as in a light dimmer.

## What Do You Mean by Audio Transformer?

Audio transformers are specially designed to be used in audio circuits. They provide a way to improve signal gain in some applications and to induce signal loss in others. They also provide a function called impedance matching. These have been used in audio systems for a very long time, including telephones. Audio transformers are oftentimes designed to be very compact so that they do not significantly increase the weight or bulk of the devices to which they are attached.

Audio transformers are also used to isolate devices from the mains power supply, which is primarily for the safety of the equipment and the operator. Devices without transformers are oftentimes less prone to suffering from interference and, because of that, they are sometimes advertised as being so, as it makes them more desirable to customers.

## What Do You Mean by Autotransformer?

In standard transformers, both the primary and secondary coils have their own windings. In an autotransformer, they share part of the winding. These transformers are oftentimes employed because they are inexpensive to manufacture and the end result is oftentimes lighter and more compact than a standard transformer.

## What Is the Name of the Winding from which the Supply Is Taken for Load Connections?

The supply is taken from the secondary winding of the transformer. The primary winding is the winding that receives the supply voltage. The secondary winding is the winding that supplies power transformed in the desired way, such as at an increased or decreased voltage or current.

## What Do You Mean by Chassis Mounting Transformer?

A chassis mounting transformer is designed so that it can be mounted easily to the chasses used to mount electrical components. They come in many standardized designs and in all capacities. These are made in many different sizes, so that they can be included in large and small devices. They are also manufactured in modular designs.

## What do you Mean by Chip Baluns?

Baluns—a portmanteau of BALanced and Unbalanced—are used to transform the impedance on a circuit. They have one balanced port and two unbalanced ports. These allow circuits to be protected from noise and perform other functions, as well. The chip versions are baluns that are contained on one IC chip.

## What Are the Advantages of Using a Transformer in an AC supply?

A transformer provides a convenient and affordable way to manipulate voltage and current. They require no moving parts, can last for a very long time and have very little loss within the system, provided that they are of a high quality.

Transformers allow electrical engineers to create devices that can have different current and voltage demands and to power them from the same wall voltage. As just one example of how versatile they are, consider the wall voltage that supplies power to your computer. Computer motherboards generally require 5V and 12V power to function. Using transformers, your power supply can reduce the wall voltage so that it is available to your computer in both of those voltages.

## What Do You Mean by Current Transformer?

Transformers can transform current as well as voltage. When voltage is stepped down, current is stepped up and vice versa. A current transformer is one that is being used to alter the current in a circuit. All transformers have some effect on the current in a circuit, but this effect is sometimes unrelated to their primary purpose in that circuit.

## What Is Called Limb of a Transformer?

The limb of a transformer is another term for the core. It is usually made out of iron and provides the winding surface for the coil. The limbs provide the substance through which the magnetic flux runs in the transformer. The current runs through the side limbs and comes together in the center limb of the transformer. The center limb is generally twice the size of the side limbs to keep this consistent.

## What Do you Mean by LAN Ethernet Transformer?

A LAN Ethernet transformer is most often used to allow voice and data networking to be done over the same wires. They are specifically designed to handle the demands of these systems and come in various designs.

LAN Ethernet transformers are generally modular devices and are oftentimes included as a part of LAN equipment.

## What Current Flows in the Transformer Primary when Its Secondary Is Open?

If the secondary circuit in a transformer is unloaded, the current in the primary is reduced to zero. Remember that this is a connected system that produces no current of its own; it merely transforms current and voltage to different ampere or volt levels.

## What Is Turn Ratio of a Transformer?

The turn ratio—oftentimes called turns ratio—is the ratio between the turns in the primary coil to the turns in the secondary coil. This determines the actual function of the transformer, such as whether it is a step up or step down transformer.

Some transformers are designed to be adjustable, so that the user can actually manually change the number of coils in the windings and increase or decrease the power output. Dimmer switches used on lighting are good examples of this.

## What Are Coil Formers Made Of?

Coil formers are typically made from high-performance plastics or other non-ferrous materials. They can be made of a wide range of different materials, depending upon the application and operating conditions of the transformer in question.

## What Do You Mean by Lighting Transformer?

A lighting transformer is one that is used specifically in applications having to do with lighting. They are commonly seen on dimmer switches. They are used both indoors and out and come in a wide variety of different designs.

Lighting transformers are generally only suited for low-voltage applications. Similar devices, however, are sometimes used to alter the voltage or current flowing to other low-voltage loads, such as hobby trains and some electrical appliances that can function at various speeds or intensities.

## What Do You Mean by Toroidal Transformers?

Toroidal transformers are round in shape. They are made from a wide variety of different materials, including the iron commonly used in most transformers. These transformers are particularly useful because of their small size. They are easy to mount and they can be easily included in devices that need to be compact. They have some disadvantages, however, such as the fact that they tend to have more limited capacity in terms of power. They also oftentimes cost more than other transformers.

## What Is the Isolation Voltage of a Transformer?

The isolation voltage of a transformer is the maximum amount of voltage that can be applied continuously to the device. This voltage flows from the input to the output or to the chassis.

Isolation transformers are transformers that are specifically used to isolate a load from an electrical connection, most often for safety purposes. Isolation voltage refers to the measure given above, isolation transformer refers to an application.

## What Is the dimming method of a lighting transformer?

Dimming lights plays into a transformer’s primary capability. The dimming function on lighting utilizes a transformer to step down the voltage coming in from the mains. For example, if you wanted to dim a light to 50% of its illumination at 12V, you could rotate the dimmer switch so that 6V are being supplied to the light. This is one of the most common ways that transformers are used in everyday life.

## How Is Magnetic Leakage Reduced Within a Transformer?

A process called interleaving is used to reduce the total amount of magnetic leakage in transformers. The interleaving helps to reduce the amount of air between the two different coils. Air doesn’t permit the magnetic flux to permeate efficiently, so putting layers of magnetic materials in an interleaved arrangement helps to make sure that the flux is subject to as little loss as possible, increasing the overall efficiency of the device.

Transformers are very efficient today and, oftentimes, they operate at 99% efficiency or above. This is what makes it practical to use ideal transformers as models for engineering. Since a 100% efficient transformer is impossible, but that benchmark is approachable, using an ideal transformer for engineering purposes makes sense.