What is a current sensor ?
2024.3.20
Articles
GOTREND Technology Co., Ltd.
1、What is a current sensor ?
A current sensor is a device that converts a large current in the primary coil into a smaller current in the secondary coil, establishing a current ratio.
The signal is converted into an analog voltage or current signal, or it can be a digital signal, and the signal can be connected to the test instrument display, and then controlled by the sensing device, called a current sensor.
Therefore, the primary coil has a high current and a lower number of turns, while the secondary coil has a higher number of turns and is connected in series with the testing instrument and protective circuit.
When the current sensor is in operation, the secondary coil circuit always remains closed, resulting in very low impedance for the series-connected coils of the testing instrument and protective circuit, effectively presenting a short circuit for the current sensor.
2、Types of current sensors :
There are many types of current sensors, including three types of current sensors :
A. Standard current sensor :
Used in testing equipment, this device generates a secondary coil current that is proportionate to the primary coil current, making it easy to measure and control within the circuit.
B. Hall current sensor :
Hall current sensors and sensors are widely used, Hall current sensors can be used in clamp DC or AC amperometers, sensors, etc. The use of ring core, generally soft magnetic ferrite and alloy materials.
C. Switch Mode Power Sensor :
Current sensors are used to detect current and voltage in a power supply control loop. A combination core of manganese-zinc power material is usually used to record the current in the control circuit.
3. What is the core type of the current sensor ?
A. Low-frequency applications, silicon steel sheets, generally apply 40-70 Hz AC signals.
B. For medium and high frequency applications, generally alloy powder, amorphous, nanocrystalline and other materials are mainly used, and 40-50K Hz signals are generally used.
C. The application of high-frequency power supply, manganese-zinc power materials, generally use 40-10M Hz signal, mainly used for high-frequency power supply.
4. Combined current sensor design
The application and development of power have evolved over time, and current sensors are becoming increasingly prevalent in power systems for measurements, protection, and monitoring. The accuracy, stability, and miniaturization of these products continue to improve.
In applications where it's not suitable to disconnect and remove wires, a combination-type current sensor is used as a replacement for conventional current transformers. Thus enabling non-disassembled installation.
By using iron oxide for the core material in an E-shaped iron core, it achieves the advantages of a simple structure, higher accuracy, and excellent linearity, thereby improving product precision.
Combination-type current sensors non-invasively sense and measure the current within an electrical circuit. They achieve minimal loss by measuring tiny currents, which is why current sensors are commonly used for measuring and controlling load currents in electrical circuits, with measurement frequencies ranging from low-frequency 40 Hz up to 10M Hz.
The most common types of iron cores for combination-type current sensors are EE, EP, and EF. They are compact in size and come in various current-resistant forms, using materials like copper wire, metal enclosures, flat wires, etc. These enhancements expand the current resistance specifications or incorporate embedded plastic molding to increase the accuracy of combination-type current sensors, meeting the requirements of higher-level applications.
