Expert Transformer Applications in Australia

Distribution transformers are among the most widespread on the market. Installed in residential, hospital, metro and industry buildings, they can feed different types of systems that do not require special services. This category of electric machine often takes the quality/price ratio into account without considering energy efficiency. GBE, in addition to offering high-quality transformers, proposes more energy-efficient machinery. This results in greater savings and less pollution. 

The new European directives actually require improvements that will lead to transformers with a better performance and lower environmental cost. In addition to the standard machinery, with traditional grain-oriented core, GBE offers transformers with an amorphous core. This technology allows for high performance and low losses to be achieved.

Fields of application: construction, industry, transport, etc.

The transformers for converters are made specifically to power loads whose waveform is not linear and the harmonic content not negligible. They can be produced with a single secondary (6 – Pulse) or multiple secondaries (12, 18 and 24 – Pulse) phase shifted between themselves.

Transformers with different secondaries are indispensable when you need to reduce the harmonic distortion generated on the power line or when it is required by the system that will be connected. The construction methods may vary depending on the type of converters being connected and the electrical parameters required by the customer. In fact, many factors and issues should be taken into account due to the presence of non-negligible harmonic content in current and voltage.

During the design, common problems should always be considered. These often include the machine overheating, (caused by a temperature increase from harmonics creating localised magnetic fields), stress on the magnetic iron core (created by harmonics under voltage, which may result in the saturation phenomena, especially when no decoupling reactor is present in the system).

To overcome these problems, the secondary side is provided with a greater insulation, because overvoltages are higher compared to those present on a line load.

Fields of application: induction furnaces, power supplies of large engines, installations and systems that require power control.

Step up transformers are designed to increase voltage. It is usually connected immediately after a generator or at the beginning of two lines with different voltages. Considering the specific application of this type of transformer, during the design phase, GBE takes into account the voltages with which the machinery will work. This allows us to be able to offer a customised product according to your needs.

Fields of application: systems with low voltage generators that distribute in medium voltage.

The transformer for solar power plants is the interface between one or more inverters of the photovoltaic panels and the distribution line. When dealing with plants with multiple inverters, multiple windings are made by studying the impedances needed according to the system on which the transformer will be installed. 

Compared to other transformers, those intended for photovoltaic systems require a more resistant structure since they are subject to a large number of release manoeuvres. To ensure the safety of the LV windings from discharge to ground, the ground connection is not included on the powered side.

Fields of application: photovoltaic systems.

The transformer for wind power plants is used as an interface between the wind generator, powered by wind turbines and the distribution line. This type of transformer can be installed either outside or inside the wind tower. If positioned inside, the transformers can be installed at the base of the tower or on top of it.

Installing a transformer for wind power plants can present specific concerns during the design phase. The most common of these concerns are reduced space and limited heat exchange, strong vibrations and difficulty assembling and disassembling in towers.

When dealing with oil transformers, a higher class of insulation must be used to avoid trouble from temperature increases. Special oils must be used as well to minimise the risks related to flammability. The wind power sector provides for stricter environmental legislation in this area, E3 environmental class, to ensure proper operation in extreme weather conditions.

Starting motors transformers are designed to work primarily with large motors. A key characteristic of this type of transformer is the high current. This is due to the absorption of the motor during the startup process, followed by a period of operation at the nominal current. While they may be undersized with respect to the nominal motor current and the transformers to be connected to the motors, it is always necessary to keep in mind the most appropriate dimensions. This ensures proper thermal and mechanical operation during startup.

Field of application: installations of large pumps, turbines, etc.

To reduce the in-rush current of the electric motors, especially on the larger ones, reduced voltages are used. The auto-transformer for motor startup usually occurs with sockets of 75 percent, 70 percent and 65 percent compared to the nominal voltage value. This way, the motor is started at a reduced voltage to then be connected to the mains and then the transformer is de-energised. 

The dimensions of the motor are usually smaller, given that it has very brief operating periods (about 30 seconds). As in the case of transformers for startup, during the design phase, it is necessary to consider the correct thermal and dynamic dimensioning. If particular applications are required, the client must establish any voltage drop limits on the motor during startup.

Field of application: startup of large motors with reduced current.

Better known as earthing reactors, these three-phase machines are used to create an earthing point in systems where it is not present (on all insulated neutral lines). With this type of transformer, any faulty currents can be assessed and used in conjunction with Petersen Coil to ensure the correct operation of the line. This is true even in the event of a grounding fault. In some cases, they are provided with a small power auxiliary to provide power to auxiliary power supply circuits. 

Because it is always necessary to consider the very low ground impedance, ensuring correct short circuit voltage on the auxiliary winding, the grounding transformer is built using unique construction methods. Given that the power of the auxiliary is variable, a value that can go from the grounding power up to a lower power of around a hundred times, it is necessary to carefully choose the type of construction to ensure the impedances requested. 

Field of application: to create a neutral

The Scott-T transformer is used to detect a bi-phase voltage from a tri-phase source. Its main advantage is the ability to obtain a balanced load on the tri-phase side with a balanced bi-phase load. Initially, it was used to power induction motors, but today it is also used in industrial furnaces, heating plants or even in traction substations.

The Scott connection comprises two special single-phase transformers (called Main and Teaser) connected to one another. This way, if the system is powered with a tri-phase power supply (with a 120 degrees phase shift), a bi-phase output is obtained (with a 90 degrees phase shift).