Buying a Good Transformer
Transformer requirements change considerably based on the load and application. Many factors have to be assessed cautiously during the purchase process to ensure that the transformer selected meets some fundamental needs. With so many sellers offering transformers that differ in features, how will you ensure that you pick the most suitable one? You need to pay attention to the factors explained in this article.
Choose between liquid-filled and dry-type transformers. The two major types of transformers are dry-type and liquid-filled. You should establish which one is suitable for your needs. Generally accepted performance features show that liquid-filled ones are more efficient, have a longer life expectancy, and have a higher load capacity. They are good at lowering hot-spot coil temperatures. However, they have a higher peril of flammability, unlike dry-type ones. At times, liquid-filled units need containment troughs to shield against fluid leaks. On the other hand, dry-type transformers are usually utilized for lower ratings. Another thing to aid in the selection is whether your transformer is for outdoor or indoor uses. Lower capacity indoor transformers are generally dry-types, while higher capacity units utilized outdoors are nearly always liquid-filled.
Next, pay attention to the winding material. Transformers utilize aluminum or copper for windings. Aluminum units are generally cheaper and often the most cost-effective. The ones wound with copper are smaller as copper is a great conductor and copper also adds to the coil’s higher mechanical strength. In order to choose the best between these two units, it is good that you work with the transformer manufacturer so that he or she can assist you in evaluating them and determining the best for your needs. The core material is another aspect to be concerned about. Core selection is a vital consideration, and core losses ought to be determined correctly. Losses that arise in the core emanate from eddy and hysteresis currents. Top-tier magnetic steel must be utilized to reduce hysteresis losses, and laminated cores are good to lower eddy current losses.
The next thing you must pay attention to in choosing a transformer is the insulators. Dry-type units usually employ insulators manufactured from fiberglass-reinforced polyester casting compounds. These insulators come with a rating of up to 15kV and are meant to be utilized indoors or in a humidity-proof enclosure. Liquid-filled units typically utilize porcelain insulators that are available in voltage ratings surpassing 500kV. Porcelain insulators are easy to clean, track resistant and useful for outdoors. High-voltage porcelain insulators have oil-impregnated paper insulation that works as capacitive voltage separators to supply even voltage gradients. Machinists must carry out power factor checks at particular intervals to prove that these insulators are in a good state.
Finally, consider accessories. Necessary accessories add costs and must be selected wisely. Examples include cabinets for additional corrosion protection, weather shields for outdoor transformers, special paint/finishes for acidic environs and ultraviolent light, rodent guards, protective provisions for damp environs, space heaters to avert condensation during a stretched shutdown, and changing control apparatus. Determine which accessories are necessary for your case and buy from reputable yet price-friendly stores.