What Is an Edge-Wise Coil?
An edge-wise coil is a coil made of rectangular flat wire with a rectangular cross section of wire as the conductor.
Unlike coils in which wires with a round cross section are wound on a bobbin as usual, these coils have a structure in which thin plates that match the size and shape of the coil are processed and stacked so that the current flows in a spiral shape. As a result, it has the appearance of laminated fins.
Uses of Edge-Wise Coils
Edge-wise coils are used in electronic circuits, for example, in DCDC converters, and as coils that temporarily store energy in switching circuits. Products include power adapter units, DCDC converter units, inverter units, battery chargers, motor driver units, generator units, and motor units.
They are used in products that handle relatively large amounts of electric power, and a variety of products are manufactured for electric power-related and automobile-related businesses. They are often used in the field of power electronics, and are used by electromagnets, such as inductors, motor units, and generator units in circuits that require large currents of over 10A.
Principle of Edge-Wise Coils
Coils required in circuits that handle large amounts of power must carry large currents. To increase the current in the coil, the cross-sectional area of the wire in the winding must be increased.
Formula: L = (A X 4π2 X μS X A2 X N2) ÷ B (B Is the Length of the Coil)
As shown in the formula for the inductance of a solenoid coil, to obtain a high inductance, the coil length value, which is the denominator in the calculation, must be small. In other words, the shorter the total length of the coil, the higher the inductance.
Therefore, edge-wise coils use a flat wire as the winding wire to increase the cross-sectional area while reducing the length of the coil to achieve high inductance.
Edge-Wise Coil Structure
Edge-wise coils are made by rolling copper wire into a spiral shape. Therefore, the winding bobbin, which was essential for conventional wire wound coils, may not be necessary, and coils that could not be produced before due to restrictions imposed by the bobbin lineup may be produced.
If a coil that requires a bobbin other than a ready-made bobbin were to be made using the conventional method of using a bobbin for winding, a great deal of time and cost would be required to design a special bobbin and make a mold. However, since the bobbin itself is not required, coils can be developed without such labor and cost. In terms of freedom of development and design, edge-wise coils are very attractive devices.
How to Choose an Edge-Wise Coil
Some manufacturers offer edge-wise coils as ready-made products, while others offer custom-made products. Many of the off-the-shelf product lineups support high currents and are suitable for power system product development.
We have a full lineup in the industry, including inductances for power circuits that exceed 10A. On the other hand, in the case of custom products, we may be able to respond flexibly by inquiring about electrical performance as well as size, shape, and other arbitrary requirements.
Other Information About Edge-Wise Coils
Advantages of Edge-Wise Coils
The advantage of edge-wise coils is that they allow for greater electrical design freedom in, for example, inverter circuits. Higher inductance can be obtained because the length of the solenoid shape can be reduced compared to a solenoid coil wound with a wire having a round cross section of the same cross-sectional area. Another advantage is that it can contribute to the design of generator units and motor units in terms of higher power, smaller size, and heat dissipation performance.