Facts About Three Phase Transformers
Three phase transformers are electrical devices designed to transfer an alternating current or voltage from one circuit to another. It is commonly used to change voltage levels through the process of electromagnetic induction. A typical electrical transformer consists of a ferromagnetic core and two or more coils called windings. Three phase transformers consist of three sets of primary and secondary windings that are wound around one leg of an iron core assembly.
A changing current in the primary winding produces an alternating magnetic field in the core. The core then multiplies this magnetic field, thus producing a varying voltage in the secondary winding. This phenomenon is called mutual induction. Basically, the power generation company generators produce electricity by rotating three coils or windings through a magnetic field in the generator. As the coils or windings rotate through the magnetic field, they create power which is sent out on three lines as in three-phase power. In a three phase transformer, the three coils are connected in the proper sequence for several reasons: so that the incoming power are matched; the power company voltage are transformed to the voltage needed; and the proper phasing or polarity is maintained.
The coils of wire are insulated are insulated from one another. In many transformers, such as low voltage transformers and step up transformers, the coils are wound on a core made with materials of high magnetic permeability. The high magnetic permeability property enhances the magnetic field induced by the current in the primary winding. The primary and secondary electric currents are inversely proportional to the number of turns in the electric coils. Meanwhile, the cores can be manufactured as either toroidal or laminated. Toroidal cores usually feature copper wire wrapped around a cylindrical core.
Electric transformers are packaged in different sizes, from a thumbnail-sized coupling transformer inside a stage microphone to huge transformers used in national power grids. Although design varies, all transformers operate with the same basic principles. Transformers are important for high voltage transmissions, making long distance transmission cost effective and economically practical. Different brands of three phase transformers handle the windings in different ways. Federal Pacific’s transformers, including the pole mounted ones, have their primary windings pre-connected in a Delta configuration. Thus, when they are connected to a three-phase source, each primary winding will have the same voltage across it. When three phase electric converters with Delta-connected primaries are connected to a 30, 4-wire supply system, the fourth wire is unused or neutral. A transformer table can be used to determine the full load current of transformers of different voltage and kVA ratings.
Aside from Federal Pacific, other manufacturers of electric transformers include Bristol Park Ind., Delta Group, Bel Volt Sales Ltd., Hammond, Engineered Component Ltd., Tensor Resources Inc. and Rondar Inc. Several factors must be considered when searching for three phase transformers. These factors include maximum secondary voltage rating, maximum power rating, maximum secondary current rating, and output type. An electric transformer may provide more than one secondary voltage value.
