Rectangular Core

Rectangular Core Product Description

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In inductor design, Rectangular Core usually refers to the RM core (Rectangular Module). The RM core consists of two magnetic cores, a coil, a single or multi-section coil bobbin, and two fixing clips. It has a high packaging density on printed circuit boards, and due to its closed design, it has advantages such as low stray fields, frequency selectivity, and electrical stability.

 

In addition, the Rectangular Core can also be an iron core with a rectangular cross-section made by winding silicon steel sheets. The magnetic flux path of this iron core is completely closed with no magnetic flux leakage, and it has optimal magnetic properties. It is suitable for equipment such as current transformers and voltage transformers ranging from 0.38kV to 330kV.

 

Rectangular Core Material Selection

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The material of the rectangular core is selected according to the working frequency, power, and performance requirements of the equipment it is applied to. Common materials include:

 

• Silicon steel sheet (electrical steel sheet)

The most widely used material for low-frequency (such as 50Hz/60Hz power frequency) rectangular cores, such as in power transformers and industrial inductors. Silicon steel sheets have high magnetic permeability and low magnetic hysteresis loss.

 

According to the processing method, they can be divided into oriented silicon steel sheets (with higher magnetic permeability in the rolling direction, suitable for cores with unidirectional magnetic flux) and non-oriented silicon steel sheets (uniform magnetic permeability in all directions, suitable for cores with alternating magnetic flux in multiple directions).

 

• Ferrite material

Suitable for high-frequency scenarios (such as tens of kHz to hundreds of MHz), such as inductors in switching power supplies, radio frequency (RF) inductors, etc. Ferrite has high resistivity, which can significantly reduce eddy current loss at high frequencies, and its magnetic permeability is adjustable according to the composition. 

 

• Amorphous alloy

A new type of magnetic material with excellent magnetic properties, such as extremely low magnetic hysteresis loss and high magnetic permeability. Rectangular cores made of amorphous alloys are often used in high-efficiency transformers (such as energy-saving power transformers) to further improve energy conversion efficiency, but their production cost is relatively high. 

 

Rectangular Core Application Fields

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Rectangular cores are widely used in electrical and electronic equipment due to their simple structure, easy processing, and good compatibility with rectangular windings. Typical applications include: 

 

• Transformers

Power transformers: Low - voltage distribution transformers (such as household 220V transformers) and industrial power transformers often use E - I type or C - type rectangular cores, which are made of silicon steel sheets to adapt to the power frequency working environment.

 

Audio transformers: Used in audio equipment (such as amplifiers), rectangular cores made of high - permeability silicon steel sheets or permalloy are adopted to ensure low distortion of audio signals. 

 

• Inductors

Choke inductors: In power electronic circuits (such as rectifier circuits), rectangular core choke inductors are used to suppress ripple current. The material can be silicon steel sheets (low frequency) or ferrite (high frequency) according to the working frequency. 

 

Filter inductors: In switching power supplies and communication equipment, rectangular core filter inductors are used to filter out high - frequency interference signals, and ferrite materials are commonly used. 

 

• Special motors

Some small DC motors or stepping motors with compact structures use rectangular cores as stator or rotor cores to reduce the overall volume of the motor and improve space utilization. 

Rectangular Core Advantages

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1. Simple processing and low cost: The rectangular cross - section is easy to cut and punch, and the production process of laminated cores is mature, which is conducive to mass production and cost control.

 

2. Good compatibility with windings: Rectangular windings can be closely matched with rectangular cores, reducing the air gap between the winding and the core, thereby reducing magnetic leakage loss and improving the utilization rate of magnetic flux.

 

3. High space utilization: In equipment with limited installation space (such as electronic instruments and automotive electronics), rectangular cores can be better arranged to fit the internal structure of the equipment, saving space.