Comprehensive Product Information Advantages Comprehensive Transformer Design Informaiton Specification Sheet for Torodial Transformers Quality in Design & Production Bridgeport Magnetics News & Press Releases Schedule of Trade Shows Contact Bridgeport Magentics The History of Bridgeport Magentics Frequently Asked Questions Bridgeport Magentics Site Map
 
 

    DESIGN ADVANTAGES OF TOROIDAL POWER TRANSFORMERS

    Toroidal Transformers are smaller, lighter, more efficient, quieter and safer than conventional stacked E/I lamination transformers. Please see below for details.
     
    The Bridgeport Magnetics Advantage
    We are cost driven and price aggressive. Our advanced production techniques use in-house developed high speed winding equipment that can produce toroidal transformers in low to medium size volumes at practically the same prices as conventional laminated transformers. For higher power ratings (500VA or up) our prices are typically lower than E/I lamination transformers. High volume orders are wound at our Asian partner’s factory based on our design and construction details.

    Versatile Application
    The application of toroidal power transformers is similar to that of stacked lamination type transformers. Most traditional circuits and calculations for rectification and filtering apply. Toroidal transformers can be designed in many sizes with a variety of secondary and primary windings, special electrostatic shielding, stray field protection, and mounting configurations.

    See our transformer performance comparison data.

    What's Special About Toroids?
     The core of the toroidal transformer is made of a grain-oriented silicon steel strip wound under controlled tension into a "donut." It is mechanically very solid and stable. Because of the way primaries and secondaries are wound uniformly around the core and the fact that toroids have no air gaps, there is very low emission of stray magnetic fields or EMR (Electro-Magnetic Radiation).

    • Smaller Size and Weight
    Toroid's higher efficiency than laminated type transformers can save up to 50% in weight and size. This helps simplify the design of cabinets, mechanical geometry, and mounting configuration. It suits the trend for smaller, more compact electrical and electronic products.

    The diameter-to-height ratio of a toroid can easily be varied (as long as area of the cross section is held constant) to suit the mechanical design. This is great for low profile equipment.

    • Low Operating Temperature
      Operating temperature is an important safety factor. Our toroidal transformers, built for Class A (105C) or Class B (130C) operation, are normally calculated for a temperature rise of 40-50ºC. If lower temperature is needed, a larger core can be used. When the transformer is operating at half its load, the temperature rise is only 1/4 of the rise at full power.

    Low Stray Magnetic Fields
     Toroids emit very low radiated electro-magnetic fields, typically 1/8 the level of the conventional E/I lamination type. For most applications no special shielding is needed. This suits toroidal power transformers for applications in sensitive electronic equipment, such as low level amplifiers, medical equipment. When further reduction of the EMR is needed, a magnetic shield around the circumference of the transformer can be provided. Encapsulation in a steel can, further reduces possible hum and adds a cosmetic benefit.

    • Low Mechanical Noise (Hum)
    The uniform windings enveloping the core greatly reduce magnetostriction - the main source of the audible hum found in conventional laminated transformers. Compared to those transformers, our toroids are silent. This makes our toroidal transformers ideal for hospital and office environment where an annoying hum would be unacceptable.

    • Electrical Efficiency
     There are two important reasons why a toroidal transformer is more efficient than the stacked E/I lamination type. One is that the high quality grain oriented steel is utilized at close to 100% in all areas of the core. As a result the core may operate at 15-16 kilogauss versus 12 to 14 kilogauss in the E/I design. There are no air gaps in the core, which means a no-load current draw of about 10% of that of a stacked lamination construction. The other reason is that the windings are distributed over the entire core circumference which reduces the mean length of copper wire per turn in comparison with the E/I transformer, the windings on which are located only on parts of its steel core. Accordingly, a toroidal design requires less steel and copper wire with less core and copper losses resulting in energy savings.

    • Reduced No-Load Losses
     Compared to l E/I transformers, toroidal power transformers exhibit extremely low no-load losses. In applications where a circuit sits in a "stand-by" mode for long periods, the energy cost savings can be significant. Lower operating temperature may also be beneficial.

    • Voltage Regulation
     The voltage drop under load (regulation) is much lower than that of a conventional transformer. Increasing the core size can further reduce voltage drop.

    • Easy to Mount
     You mount our toroidal transformers with a single center screw instead of four screws used for a lamination type transformer, helping you to reduce assembly time.