Types of AC Transformers

A transformer is a device that distributes electric energy from one circuit to other circuits by stepping up or stepping down the voltage. Transformers are used for a broad range of applications, including lowering the voltage of traditional power circuits to run low-voltage devices like doorbells and toy electric trains and raising the voltage of electric generators to allow for long-distance transmission of electric power.

Transformers alter voltage using electromagnetic induction. Current is generated in a secondary coil as the flux lines rise and collapse in response to changes in current travelling through the primary coil. The secondary voltage is calculated using the turns ratio: the ratio of the number of turns in the secondary coil and the number of turns in the main coil.

An AC transformer is an electrical device that is used to change the voltage in alternating current (AC) electrical circuits.  AC transformers have advantages over DC transformers as they can be stepped up or stepped down as per the usage, which cannot be done with DC transformers. 

Types of AC Transformers

Transformers are classified based on their function, application, and construction. The classifications may sometimes overlap — for example, a transformer can be both a three-phase and a step-up transformer. 

Here are some types of transformers:

1. Transformers with a step-up and a step-down function: Step-up transformers convert low voltage (LV) and high current on the primary side of the transformer to high voltage (HV) and low current on the secondary side. Step-down transformers convert the high voltage (HV) and low current to the secondary side’s low voltage (LV) and high current.

2. Single-Phase and Three-Phase Transformers:  Single-phase transformers are less cost-efficient than three-phase power systems. However, when space is restricted, a bank of three single-phase transformers is preferable to a single three-phase transformer since it is easier to transport.

3. Transformers for electricity, distribution, and instrumentation: Power transformers are often used to scale up or decrease the voltage level in transmission networks. It is most efficient at or near full load; thus, it is used mostly at high or peak loads.

A distribution transformer reduces the voltage for distribution to household or commercial consumers. It features superb voltage control and runs 24 hours a day at 50% of full load for optimal efficiency. 

Instrument transformers decrease large voltages and currents to smaller values than ordinary instruments can monitor.

4. Autotransformers with Two Windings: When the ratio of the high and low voltage sides is more than 2, a two-winding transformer is often employed. Using an autotransformer is more cost-effective when the ratio of high to low voltage sides is less than 2. 

5. Oil Cooled and Dry Type Transformers: This category includes the transformer cooling system. Transformer oil is used to cool oil-cooled transformers. In the dry type transformer, air cooling is used.

6. Air-core transformers: Air-core transformers have two or more coils wound up in a solid insulating material or an insulating coil shape (i.e., the currents required for radio transmission) to transfer radio-frequency currents. Iron-core transformers provide similar functions in the audio frequency range.

Types of Transformers based on Windings

Transformer windings may be divided into two categories: 

1. Core type Transformer: Two vertical legs or limbs and horizontal yoke portions comprise a core type transformer. The magnetic circuit is universal, and the core is rectangular. Cylindrical coils are installed in both limbs (HV and LV).

2. Shell Type Transformer: A core limb and two outside limbs make up a shell-type transformer. On the middle limb, HV and LV coils are inserted. There is a dual magnetic circuit.

3. Berry Type Transformer: The spokes of a wheel may be seen in the core of a berry transformer. This kind of transformer is contained in transformer oil-filled tight-fitting metal sheet tanks.

Structure of AC Transformer

A transformer’s core is a magnetic circuit. The main and secondary windings enable electricity to flow through the core. An alternating current flows when an alternating voltage is supplied to the main winding. The alternating current generates a magnetic field in the winding that fluctuates in strength and frequency. The magnetic flux of a transformer fluctuates with AC voltage frequency. 

A transformer has two or more coils joined by an iron core. A transformer’s winding is the insulated copper wire wound around an iron core.

A transformer’s primary winding receives the input voltage. The main coil is so named because it is on the top. The alternating voltage on the primary coil creates an alternating magnetic field. The secondary coil receives magnetic flux from the iron core. The secondary side of the transformer may be used to acquire the output voltage. The secondary coil corresponds to the main coil. 

The output voltage is determined by the winding ratio of the main and secondary coils. The output voltage is greater when the secondary coil has more turns than the main coil. When the secondary coil has fewer turns, the output voltage is lower. If both coils have the same number of turns and are wire wrapped, the output voltage is the same. A transformer’s main job is to convert AC to DC voltage. The turns ratio is crucial for power, voltage, and current changes. When transformers modify the voltage or amperage, the reverse lessens or increases.

Conclusion

Transformers come in various shapes and sizes to suit a variety of applications. Some transformers are large enough to be utilized with charging cradles and are often found at generating stations or power plants. They serve the same goal regardless of form or size: to transmit electrical power.