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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: