Comprehensive Guide To The Distribution Transformer

A transformer that give the final transformation in the voltage is known as a distribution transformer. It is also known as a service transformer because it provides enormous service. It is made by AC power distribution which is helpful for practical purposes efficiently.

Transformers were establish as early as 1882. If mount on a utility pole, they are call pole mount transformers, or if the distribution lines are locate at ground level or underground, then it is known as a pad transformer.

Distribution transformers usually are mount on concrete pads and locked in steel cases. Distribution transformers typically have ratings less than 200 class. However, national standards can describe units up to 5000 classes. Distribution transformers are provoke to work 24 hours a day, even when they don’t carry any load.

As per best distribution transformers manufacturers India these transformers do not produce a high iron loss. When the transformer contains lesser loads, it is assumed to have maximum efficiency. If you need better efficiency, then you must reduce the voltage in distribution transformers.

Regardless of size or shape, a transformer does the same thing that transforms or changes the voltage and current value. A transformer that changes voltage from lower values to higher values is usually refer to as a step-up transformer; step-up transformers are commonly use in transmission systems in a distribution system.

Transformer Features

However, you’re most likely going to find step-down transformers that change the voltage from higher values to lower values. In this article, you will learn a basic understanding of how transformers work and teach you how to recognize the typical types of transformers you will find in distribution systems.

In general, the transformers you will find in distribution systems have three elements in common: a metal core, a primary winding, and a secondary winding.

Voltage is apply to the transformer through the primary winding and taken off the transformer through the secondary winding; when voltage is apply to the primary winding, the resulting current creates a magnetic field or the core that induces a voltage in the secondary winding.

The ratio between the number of turns in the primary winding and the number of turns in the secondary winding determines whether the voltage induced in the secondary has a higher or lower value than the applied voltage.

In most distribution transformers, the voltage induce in the secondary winding is lower than the voltage apply to the primary winding. In this example of a step-down transformer, one end of the primary winding is grind. A tap coming off the center of the secondary winding is also grind. This results in one primary lead coming into the transformer, and two secondary leads plus ground is coming out of the transformer.

Therefore, they are manufacture by Distribution transformers manufacturers India to have lesser leakage reactance.

Pole Top transformer

This type of transformer is recognize by the cylindrical housing, the extensive primary bushing on the top of the housing, and three secondary bushings on the housing side. This illustration is similar to the kinds of transformers you see on many overhead distribution systems.

Both the primary and secondary bushings insulate the transformer leads as they pass through the housing. The primary winding in this transformer is supply with primary distribution voltage from a distribution line on the pole. Primary voltage is apply to this lead and runs through the primary bushing to one end of the primary winding. The other end of the winding is tie to the transformer’s housing, and an external ground is apply.

The secondary or utilization voltage induce in the secondary winding is tap off the transformer through leads passing through the secondary bushings on the housing side.

In this type of transformer, the lead passing through the secondary side is grind. The leads on either side are hot. The secondary leads are usually connect to wires that form a secondary bus which supplies consumers with electricity through service drops.


The elements that allow you to recognize this component as a transformer include:

First, it has a large primary bushing on top connected to a distribution line. Second, smaller secondary bushings are located on the side of the housing. Finally, the wires coming off the secondary bushings form a secondary bus and service drop going to a customer.

Pole transformer with large bushing

The other type of pole top transformers also looks and works exactly like the above one. The only difference is the large bushing on the top of the housing. This transformers has two bushings. It allows the primary lead to connect to the primary winding just like the previous one.

However, the end of the primary winding grounded through the transformer housing. This type of transformer is grind through the second bushing. Both single pushing and two bushing transformers perform the same thing, and they look a little different.

In some cases, the load demand and equipment used by a consumer acquires the use of a three-phase transformers in an overhead system; three single-phase transformers can be connect to form a three-phase transformer of course, not all transformers are locate overhead on utility poles in areas that have underground distribution systems.

Pad mounting transformer

Pad mounting is a standard method of installing transformers. This three-phase transformer is house in a rectangular-shape metal cabinet that sits on a concrete pad; all connections for the transformer are conceal within the cabinet. Single-phase pad-mounte transformers are similar in shape, but their cabinets are usually smaller; inside the cabinet are the primary bushings and the secondary bushings.

Some types of transformers are installe underground in specially construct vaults for protection. Thus, transformers are an essential part of a TND system because they change the voltage and current value to meet the system’s specific needs.


Hence, in this article, we have shared complete details about distribution transformers. Distribution transformers manufacturers India provides several types of transformers for a variety of uses for commercial and residential purposes across the globe.


Related Articles

The comment has been closed!
Back to top button