Power Transformers raise or lower the voltage as needed to serve transmission or distribution circuits.
Power transformers transform electrical voltage from one level or phase to another, usually "stepping down" voltage from a higher to a lower level. This is accomplished through the principle of magnetic induction between coils to convert voltage and/or current levels. Power transformers include a broad range of electrical transformers, such as autotransformer, control transformer, current transformer, distribution transformer, general-purpose transformer, instrument transformer, isolation transformer, and potential (voltage) transformer.
Power transformers can be configured as either a single-phase primary configuration or a three-phase configuration. Other important aspects to consider when specifying power transformers may include:
- Maximum secondary voltage rating
- Maximum secondary current rating
- Maximum power rating
- Output type.
Power transformers can be manufactured as either a toroidal or laminated transformer. The differnce is that toroidal transformers typically have copper wire wrapped around a cylindrical core so the magnetic flux (which occurs within the coil) doesn't escape. The coil efficiency is superior, while the magnetic flux has hardly any influence on other transformer components. On the other hand, laminated power transformers contain laminated-steel cores. This means that steel laminations are insulated with a nonconducting material, such as varnish, and then formed into a core that reduces electrical losses.
See also: Power Transformers Construction
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