High Voltage Transformers Explained

High voltage transformers convert voltage from one level or phase configuration to another, usually high to low.They can include functions for electrical isolation, power distribution, and control and instrumentation applications.This transformer design relies on the principle of magnetic induction between coils to convert voltage and/or current levels.They can be configured as a single-phase primary configuration or a three-phase configuration.As you move down the primary high power voltage winding list, the size and cost of the transformer increases.Single-phase primary configurations include single-wire, two-wire, four-wire (2+2), 5-wire and trapezoidal.A 5-lead primary requires more copper than a quad (2+2) primary.Ladders are the least economical primary configuration. Three-phase transformers are connected in a delta or star configuration. A star-delta transformer has its primary winding connected in star and the secondary winding connected in delta.A delta-star transformer has its primary winding connected in delta and the secondary winding connected in star.Three-phase high voltage power configuration options include Delta-Delta, Delta-Wye (Y), Wye (Y)-Wye (Y), Wye (Y)-Delta, Wye (Y)-Single Phase, Delta- single phase, and international.Primary frequencies that can be used for the primary input voltage signal of a power transformer include 50 Hz, 60 Hz, and 400 Hz. 50 Hz is a common frequency for European power supplies. 

60 Hz is common in North American electricity. 400 Hz is most widely used in aerospace applications.The maximum primary input voltage rating is another important parameter to consider.If the transformer is to be used for multiple nominal voltages and to avoid short circuits, the transformer should be provided with more than one primary winding.Other important specifications to consider when searching for a high voltage transformer include maximum secondary voltage rating, maximum secondary current rating, maximum power rating, and output type.A transformer can provide more than one secondary voltage value.The power rating of a transformer is the sum of the VA (volts x amps) of all secondary windings.Output choices include AC or DC. For AC current waveform outputs, voltage values are usually given in RMS values.Consult the core transformer manufacturer for waveform options.For DC secondary voltage output power supplies, consult the manufacturer for rectification type.They can be constructed as toroidal or laminated transformers.Toroidal pulse transformers are generally copper wires wound on a cylindrical iron core, the magnetic flux generated inside the coil will not leak out, the coil efficiency is good, and the magnetic flux has little influence on other components.Laminated transformers contain a laminated steel core; they are also known as E-I transformers.These steel laminations are insulated with a non-conductive material such as varnish and then formed into a core to reduce electrical losses.Power transformers can be one of several types.These include autotransformers, control transformers, current transformers, distribution transformers, general purpose transformers, instrumentation transformers, isolation transformers, voltage (voltage) transformers, power transformers, step-up transformers, and step-down transformers. Available mounting options include chassis mount, dish or disk mount, enclosure or freestanding, H-frame and PCB mount.

Power Transformers

Power transformers convert voltage from one level or phase to another, usually "stepping down" the voltage ratio from a higher level to a lower level. This is achieved through the principle of magnetic induction between coils to switch voltage and/or current levels. Power transformers include a wide range of electrical transformers such as autotransformers, control transformers, current transformers, distribution transformers, general-purpose transformers, instrument transformers, isolation transformers and voltage (voltage) transformers.There is a difference between power transformers and distribution transformers operating at normal levels.Typically, power transformers are used in power transmission networks (using higher voltages) for step-up or step-down applications (400 kV, 200 kV, 110 kV, 66 kV, 33kV), usually rated above 200MVA. Utility distribution transformers are put into operation in power distribution networks as a means of converting power to a level (11kV, 6.6kV, 3.3kV, 440V, 230V) that can be used by end users, usually rated below 200MVA.

The PT can be configured as a single-phase primary configuration or a three-phase configuration. Other important aspects to consider when specifying may include:

1. Maximum secondary output voltage rating.

2. Maximum secondary rated current.

3. Maximum rated power.

 Output type

1. Electronic Component.

2. Primary and secondary windings.

The PT provides a variety of AC power to the system with various primary and secondary voltage levels and suitable current values from the primary and secondary windings (depending on the turns ratio) and the magnetic field. In addition, it may be necessary to provide electrical isolation between the electronic circuit and the external common power supply.A functioning PT can be manufactured as a toroidal or laminated transformer.The difference is that toroidal transformers typically have copper wire wound around a cylindrical laminated iron core so the magnetic flux (which occurs inside the coil) cannot escape.Coil efficiency is superior, and magnetic flux has little effect on other transformer components. Laminated PTs, on the other hand, contain a laminated steel core.This means that the steel laminations are insulated with a non-conductive material such as varnish, which then forms the core to reduce electrical losses.