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What Is A Transformer?
From the original power source, such as the utility generator, transformers of medium- to high-voltage are used to step up or to step down voltage for the most efficient and cost-effective transmission of electrical energy. They can be found in utility switchyards, on power poles, in shopping centers, schools, manufacturing and process plants and more. Proper maintenance of transformers is critical, and proper preparation for re-application is no less critical.
A transformer transfers electrical energy from one circuit to another through inductively coupled conductors — the transformer's coils. A varying current in the first or primary winding creates a varying magnetic flux in the transformer's core and thus a varying magnetic field through the secondary winding. This varying magnetic field induces a varying electromotive force (EMF), or "voltage," in the secondary winding. This effect is called mutual induction.
Main Components of Industrial Transformers
Industrial transformer parts and assemblies include but are not limited to:
Common Types of Industrial Transformers
Common types of electrical transformers found in industry include, but are not limited to low- voltage dry type (600V AC max. primary), low-voltage transformers control power, low-voltage transformers instrumentation voltage, low-voltage transformers instrumentation current, medium-voltage transformers dry-type, medium-voltage transformers padmount oil filled, medium-voltage transformers padmount gas filled and medium voltage transformers power oil filled.
Low-voltage transformers can be found in industrial, commercial and residential applications. As with medium-voltage units, low-voltage transformers are fed (primary) with one voltage and produce (secondary) a different voltage. Most common are step-down transformers. In your place of business, the most common transformers are dry type air-cooled units of single or three phase that transform 480V to 240V, 208V or 120V.
Medium-voltage transformers with voltages ranging from 1500V to 72,000V are sometimes dry or air insulated but most often they are liquid filled, usually with 10c mineral oil but sometimes with high flashpoint insulating fluid such as silicon fluid or R-Temp (reg) and several others.
In addition to indoor dry-type enclosures, there are dry-type weatherproof enclosed transformers and dry-type compartmental transformers. Some dry transformers are parts of unitized substations integrating primary and secondary switchgear in a common cabinet. Unitized substations can also be assembled using liquid-filled transformers; both can be trailer mounted for portability. Another type of dry type unit is cast coil, in which a pre-wound coil is fully cast within an epoxy capsule, making it nearly impervious to environmental elements.
Compartmental transformers, often referred to as “padmount,” are designed for high public traffic area installation so they are made tamper-proof. All primary and secondary connections are made on the same side of the transformer in separate chambers behind separate lockable doors.
ROMACs Industrial Transformer Inventory
Specialty transformer OEMs:
ROMAC's Reconditioned Industrial Transformers
Reconditioning is the process of returning electrical equipment to safe and reliable operating condition based upon the design of the original manufacturer at the time of manufacturing. ROMAC regularly carries inventory from all the major transfomer manufacturers, including: MGM, Hammond, ACME, Federal Pacific, and SOLA. ROMAC follows PEARL industry standards to recondition a transformer, including procedures to test, inspect, disassemble, recondition and validate test the product. Reconditioning procedures include disassembly, cleaning, drying, deoxidizing, removal of corrosion, degreasing, plating, painting, lubricating, adjusting, filtering and adding or replacing oil or gas. After reconditioning, subassemblies can be reinstalled in the now cleaned and painted enclosure or frame, including the addition of upgrades or options to improve the apparatus’s performance. Assembly of the reconditioned components and subassemblies is followed by final inspection and testing. As with all testing, inspection and reconditioning operations, final inspection and test results are recorded onto the Evaluation and Test forms included with the standard.