EI Laminated Core

  • A large portion of transformers in general use are actually EI-laminated core transformers. For instance, in much of today's equipment, a transformer with EI-core can be found (partly because of the low price of such transformers).

    The name EI-core refers to the shape of the transformer core, which is built up with E and I shaped metal plates laminated together. At Jackson Engineering we build EI Power Transformers up to 15KVA.

    At Jackson Engineering, we manufacture so that the the energy loss occurring in the EI is as minimal as possible, minimizing energy lost from heat production in the transformer.

    Our laminations are manufactured and designed with cutting edge technology: CNC progressive carbide dies, tooling CAD/CAM/CAE designed and high skilled technicians and engineers. Meeting high quality standards, we offer high reliability and energy efficiency in your appliances at competitive prices.

    We specialize in magnetic EI's used in lighting systems: EI Power Transformers are generally used with low voltage lighting systems to transform the standard voltage that is normally available (usually 120 volts or 277 volts) to either 12 volts or 24 volts.

    Our Engineers are ready to build your EI LAMINATED CORE TRANSFORMERS today at Jackson Engineering.


1) In the EI-Core Transformer, a significant portion of the core is external and is attached directly to the chassis of the equipment it is installed in. This gives any energy build-up in the core a direct path to the chassis ground of the component.
2) The other advantage EI-Core Transformers have is the small air gaps that are present when the two parts of the lamination/core are put together. These air gaps act as pressure relief valves for the magnetic flux in the core, further enhancing the transformer's resistance to core saturation.
3) Another important reason why the EI is so widely used can be attributed to the fact that the primary inductance of an EI Transformer is less affected by DC offset on the mains. When an EI-laminated transformer is used, the DC offset problem disappears. The EI-laminated transformer continues to supply AC power of the proper voltage with all the noise elimination capabilities designed into the EI transformer. This means that an EI Transformer can actually store more energy in the primary inductance, which can be released when the rectifiers conduct.

The EI-laminated core power transformer can be a superior performer if designed, manufactured and installed properly. At Jackson Engineering we design for high end quality. With a poorly designed transformer or the wrong selection, the result is often high levels of audible noise from the transformer as well as very high levels of noise getting into the power supply of the component.

We know that Performance is everything - manufacturing custom transformers since 1949, we have many different techniques for high performance. For instance, there are additional winding tricks that give EI-laminated transformers 20dB to 30dB more noise rejection than typical off the shelf transformers (toroidal). This is very significant since 20dB less noise is 1/100th of the noise of the "reference" level. 30dB less noise is 1/1000th of the "reference" noise level.

Summarizing: Our EI-Laminated Core Power Transformers are widely used where the mains quality is bad - meaning noisy, high inductance, high resistance and DC offset. The EI core is best for keeping line noise out of the circuit.

At Jackson Engineering, our EI-laminated core transformers can be made in batches on highly automated winding machinery. However, precision winding an EI-core transformer by hand, very carefully, using bi-filar winding techniques can produce some stunning custom transformer performance results, especially if wound as "low flux" design - meaning more primary turns and more primary inductance and thus more energy storage.

All of our EI Laminated Power Transformers are designed to meet all international safety requirements ( UL, CSA, TUV...)

Jackson Engineering builds CUSTOM EI CORE POWER TRANSFORMERS to your SPECS - We also provide ENGINEERING SOLUTIONS.

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