Toroidal Power Transformers convert power-level voltages from one level or phase configuration, lower magnetic leakage, lower electrical noise and mechanical hum and are excellent as isolation step-down and high voltage step-up transformers, autotransformer, ferroresonant transformer and smoothing inductor.
The closed ring shape of a toroidal transformer eliminates air gaps inherent in the construction of an E-I core. The primary and secondary coils are often wound concentrically to cover the entire surface of the core, which provides screening to minimize the core’s magnetic field from generating electromagnetic interference.
Toroidal transformers are more efficient than laminated E-I types for a similar power level. Other advantages compared to E-I types, include smaller size (about half), lower weight (about half), less mechanical hum (making them superior in audio amplifiers), lower exterior magnetic field (about one tenth), low off-load losses (making them more efficient in standby circuits), single-bolt mounting, and greater choice of shapes.
API Technologies winds their own silicon steel cores to ensure that the grain boundaries are optimally aligned, improving the transformer’s efficiency by reducing the core’s reluctance.
Ferrite toroidal cores are typically used at higher frequencies, between a few tens of kilohertz to hundreds of megahertz, to reduce losses, physical size, and weight of inductive components.
Other core types offered (but not limited to) are Iron Powder (higher permeability), Moly Permalloy (for higher accuracy), Carpenter 49 alloy (for low loss and low distortion) and 3 percent silicon steel alloy (which takes up to 4 times more voltage than Moly Permalloy).
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