What Is an Autotransformer?

An autotransformer is a transformer whose primary and secondary windings are on the same winding. The primary and secondary windings are directly connected in series and are self-coupled. According to the structure, it can also be subdivided into adjustable pressure type and fixed type. Autocoupling is the meaning of electromagnetic coupling. Common transformers transfer energy through the electromagnetic coupling of the primary and secondary coils. There is no direct electrical connection between the primary and secondary sides. The primary and secondary sides of the autotransformer have direct electrical connections. It is part of the high voltage coil. Protective devices such as autotransformers are also used in the protection of communication lines.

The secondary winding of an autotransformer is a component of the primary winding. Such a transformer appears to have only one winding, so it is also called a "single-winding transformer". The primary and secondary-side coupled inductors can be made according to the three-terminal coupled inductors with different names connected in the circuit theory.

As the calculated capacity of the autotransformer is less than the rated capacity. Therefore, at the same rated capacity, the main size of the autotransformer is small, and the effective material (silicon steel sheet and

Two or more windings on a closed iron core

Autotransformers are used in applications where primary and secondary isolation are not required. They have the advantages of small size, few consumables, and high efficiency. Common communication (manual rotation)

Auto-transformer step-down starting refers to the use of auto-transformer to reduce the

Neutral transformer

Neutralizing Transformer: A device that reduces the impact of strong wires on communication lines. Its number of secondary coils is the same as the number of communication wires, and it is directly connected to the communication wires; its primary coil string is connected to the pilot wire that is grounded at both ends. In this way, the electric current in the strong electric wire and the pilot wire will generate a corresponding ground potential to the through wire. It changes the potential distribution of the communication wires and ensures that the ground potential along the communication lines does not exceed the limit value. This serial connection method does not change the insulation of the communication line to the ground, and also plays a role in protecting the communication line. Its disadvantage is that it needs to add an additional indicator line.

Autotransformer shielded transformer

Shielding transformer (Reduction Transformer): Shielding transformer is also called reducing transformer. It works on the same principle as a neutral transformer and is used for communication cable protection. Its secondary money ring is a whole, which is wound by a section of cable core or the core of the cable itself. There is no need to separately set a secondary coil for the wire; and its primary coil is wound by insulated copper wire and directly connected in series In the skin.

Autotransformer separation transformer

Isolating Transformer: A protection device that prevents strong wires from affecting communication lines. Also called insulation transformer. Its working principle is that the primary and secondary coils with a transformation ratio of 1: 1 are respectively connected to a pair of communication wires, which separates the wires into multiple sections, reduces the induced longitudinal potential on the wires, and protects the communication lines. . It is suitable for audio communication lines, but DC tests and transmission of DC signals cannot be performed on communication lines that use separation transformers.

Autotransformer Sink Transformer

Booster Transformer: It is used in AC electrified railway power supply system and is a device used to reduce the impact on neighboring communication lines. It will forcibly absorb the current that has escaped into the ground to the specially constructed return line and introduce the current into the traction substation. It not only saves energy and reduces consumption, but also protects communication lines ^[4] .