What is a buck boost transformer?Where are buck boost transformers used and how does it work

What is a buck-boost transformer? Is a buck-boost transformer an autotransformer

A buck-boost transformer is a type of autotransformer, which can lower or raise the voltage level in the range of 5-25%. So by this, we can vary the voltage and the voltage level can be achieved between 208-240 Volts, or between 480 and 575 Volts. These transformers can be used for single and three-phase applications. Buck-boost transformers are single-phase, four winding transformers, and they are designed for two purposes. The first purpose is that it can be used to power low voltage circuits. Their second and most important purpose is as a buck-boost transformer, buck-boost means these transformers can be used to increase or decrease line voltage to match required load voltage. These transformers are used to correct consistently low or high voltage conditions, where the voltage difference ranges from 5 to 27%. Buck-boost transformer won’t stabilize variable voltage, variation in the input voltage is passed through to the output side of the transformer in the same percentage.


Where are buck-boost transformers used and its applications

Buck-boost transformers can provide great capabilities and flexibility in KVA sizes and input/output voltage combinations. Buck-boost transformer can be field connected as an autotransformer. These transformers are used where low supply voltage exists because the equipment is installed at the end of the bus system. It is also used in the supply system when it operates at or over the design capability. These transformers are used in the power distribution system and in electrical systems that have voltage sags.

What is the purpose of a buck-boost transformer and why are they used

The buck-boost transformer configuration is widely used in converting direct current voltage into another value of DC voltage, and in inverters. Inverters convert direct current into alternating current. Buck-boost transformer is also known as a push-pull transformer, and these transformers are usually preferred in high power transformer switching applications exceeding one kilowatt. Electrical and electronic equipment can operate at maximum efficiency on a standard supply voltage. If the supply voltage is constantly too high or too low it would affect the operating efficiency of the equipment. In order to maintain the proper supply voltage, buck-boost transformers can be used.

How does a buck-boost transformer work and How are they connected

A buck-boost transformer which has four winding can be connected in many ways to get a multitude of voltage and KVA outputs. A two winding buck-boost transformer can be connected only one way. The output voltage is a function of input voltage if the input voltage varies then the output voltage will vary at the same percentage. The working of the buck-boost transformer, the input voltage will be sent to the primary winding and it will increase or decrease the voltage according to its configuration and then the rectified voltage will be sent to the secondary and from there to the connected device. Buck transformers are mostly used to power low voltage circuits such as control and lighting circuits. Mostly booster transformers are used at the end of the power line so that the voltage can be increased at the required value. It is also used to control the voltage of a feeder at a point far away from the main transformer.

What is the difference between a buck-boost transformer and an autotransformer

If the primary and secondary of the buck-boost transformer is connected together electrically then it can be considered as an autotransformer. If the interconnection between the primary and secondary voltage is not made, then it is an insulating type transformer.

How to select the proper buck-boost transformer

In order to select a proper buck-boost transformer the following factors must be considered

Phase requirements – Determine the phase requirements single or three-phase

Input line voltage – Determine the supply or line voltage at the installation site where the transformer will be connected, this can be achieved by measuring the voltage with a suitable voltmeter.

Load voltage – Decide the required voltage to operate the load to be connected to the transformer.

Frequency – We must check if the supply line frequency and load frequency are the same.

Load amps or KVA – Determine either load KVA or load amps by adding all loads to be supplied by the transformer, and it can be accomplished by referring the equipment nameplates.

Why use a buck-boost transformer instead of other types of transformer

Buck-boost transformers have many advantages when compared to other types of transformers. Buck-boost transformers are efficient and they are smaller and lighter, they are versatile and have many applications, 5-10 times increase in KVA and they are of lower cost. They also have certain disadvantages such as no circuit isolation and can’t create a neutral.

How to install a buck-boost transformer

Outside installation of the transformer should have the wiring in a conduit or as required by local codes. Encapsulated transformers can be installed indoors and outdoors.