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Products & Services
Laminated Steel Transformers & Inductors
Ferroresonant
Transformers Toroidal Transformers & Inductors
Three Phase
Transformers |
Toroidal Transformers and InductorsToroidal transformers are built around a ring-shaped core, which, depending on operating frequency, is made from a long strip of silicon steel or permalloy wound into a coil, powdered iron, or ferrite. A strip construction ensures that the grain boundaries are optimally aligned, improving the transformer's efficiency by reducing the core's reluctance. The closed ring shape eliminates air gaps inherent in the construction of an E-I core. The cross-section of the ring is usually square or rectangular, but more expensive cores with circular cross-sections are also available. The primary and secondary coils are often wound concentrically to cover the entire surface of the core. This minimizes the length of wire needed, and also 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, lower weight, less mechanical hum, lower exterior magnetic field, low off-load losses, single-bolt mounting, and greater choice of shapes. The main disadvantages are higher cost and limited rating. Ferrite toroidal cores are used at higher frequencies, typically between a few tens of kilohertz to a megahertz, to reduce losses, physical size, and weight of switch-mode power supplies. A drawback of toroidal transformer construction is the higher cost of windings. As a consequence, toroidal transformers are uncommon above ratings of a few kVA.
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Advantages
Power supplies