Viji Power Transformers Pvt Ltd

Kadabagere, Bangalore, Karnataka

• SpecialityVariable speed drives (VSD) Aluminium electrolysis DC arc furnace

One of the main differences from other types of transformers is that the load currents contain higher harmonics due to the distorted waveform. The converter to the transformer causes the distorted current waveform. This has to be considered current leads to higher losses & temperatures in the transformer. Network regulations also require reduction of harmonic distortion. These transformers are used in applications where a variable speed is required on the motor shaft. They are used in a wide variety of applications such as rolling mill drives, ship propulsion systems, mine hoist drives, wind tunnels drives etc. The figure below shows a basic circuit diagram for a system configuration for a wind tunnel. The transformer is a 12-pulse unit that feed two 6-pulse rectifiers, which are connected to two inverters, which in turn is connected to a synchronous motor. The transformer is also equipped with a tertiary winding, which is to reduce the harmonic voltage distortion in the HV supply system as increasing the power factor of the load.

An iron-core transformer having a primary winding that is connected to an alternating-current power line and one or more secondary winding’s that provide different alternating voltage values. This is the most common type of transformer, widely used in electric power transmission and appliances to convert mains voltage to low voltage to power electronic devices. They are available in power ratings ranging from mW to MW. The insulated laminations minimizes eddy current losses in the iron core. Small appliance and electronic transformers may use a split bobbin, giving a high level of insulation between the windings. The rectangular cores are made up of stampings, often in E-I shape pairs, but other shapes are sometimes used. Shields betweeen primary and secondary may be fitted to reduce EMI (electromagnetic interference), or a screen winding is occasionally used.

Dry type transformers require minimum maintenance to provide many years of reliable trouble free service. Unlike liquid fill transformers which are cooled with oil or fire resistant liquid dielectric, dry type units utilize only environmentally safe, CSA and UL recognized high temperature insulation systems. Dry type transformers provide a safe and reliable power source which does not require fire proof vaults, catch basins or the venting of toxic gasses. These important safety factors allow the installation of dry type transformers inside buildings close to the load, which improves overall system regulation and reduces costly secondary line losses. Dry type transformers are a rather mature product and technology but, of all the components in a power system, a transformer replacement can be a physically challenging event, extended delivery of a replacement or repair unit and expensive transportation costs. These are transformers whose core and coils are not immersed in an insulating oil.

A distribution transformer is a transformer that provides the final voltage transformation in the electric power distribution system, stepping down the voltage used in the distribution lines to the level used by the customer. The invention of a practical efficient transformer made AC power distribution feasible; a system using distribution transformers was demonstrated as early as 1882. If mounted on a utility pole, they are called pole-mount transformers. If the distribution lines are located at ground level or underground, distribution transformers are mounted on concrete pads and locked in steel cases, thus known as pad-mount transformers. Distribution transformers normally have ratings up to 200 KVA, although some national standards can describe units up to 5000 KVA as distribution transformers. Since distribution transformers are energized for 24 hours a day (even when they don’t carry any load), reducing iron losses has an important role in their design. As they usually don’t operate at full load, they are designed to have maximum efficiency at lower loads. To have a better efficiency, voltage regulation in these transformers should be kept to a minimum. Hence they are designed to have small leakage reactant.

Furnace transformer is used to melt the metals and ores in the electric furnace. An electric arc furnace (EAF) is a furnace that heats charged material by means of an electric arc. Arc furnaces range in size from small units of approximately one ton capacity (used in foundries for producing cast ironproducts) up to about 400 ton units used for secondary steelmaking. Arc furnaces used in research laboratories and bydentists may have a capacity of only a few dozen grams. Industrial electric arc furnace temperatures can be up to 1, 800 °C (3, 272 °F), while laboratory units can exceed 3, 000 °C (5, 432 °F). Arc furnaces differ from induction furnaces in that the charge material is directly exposed to an electric arc, and the current in the furnace terminals passes through the charged material.