Common Mode Chokes (CMC)

 A choke coil is an inductor designed to have a very big reactance at a determined frequency or frequency range. The common-mode inductor is essentially a two-way filter: on the one hand, it must filter out common-mode electromagnetic interference on the signal line, and on the other hand, it must restrain itself from emitting electromagnetic interference to avoid affecting the normal operation of other electronic devices in the same electromagnetic environment.

Choke coils are widely used in electronic appliances, like television, air conditioner, refrigerator as well as in many other devices by acting like filters. Common mode choke coils are useful in a broad range of precaution of electromagnetic interference (EMI) and radio frequency interference (RFI) of feed lines and for precaution of malfunctioning of several electronic appliances. Additionally, common mode choke coils are also used in circuits like CC-CC converters and load circuits to reduce the noise resulted from the leaks of each part of feed line. SAT Amorphous is a pro manufacturer of electronic components for more than 10 years.

The Key advantages:

1. Reduction of common mode currents,

2. Lower voltage in differential mode in wirings close to points where common mode currents flow,

3. Lower electric field strength in the installation,

4. The coil act as a low-pass filter, it blocks currents originating in induced voltages in outputs to electromagnetic waves.

Please click here for more informations of common mode choke.

Teach you to confirm these two kinds of transformers

 In order to accurately measure the power consumption in high-voltage and high-current AC circuits, voltage transformers and current transformers are generally used to convert high voltage into low voltage and large current into small current, and configure a moderate meter to use voltage Transformers to carry out accurate measurements.

For example, the current, working voltage, output power, frequency and electromagnetic energy measurement and verification in the high-voltage power supply system are all measured by voltage transformers. In addition, voltage transformers are also equipment that cannot be lacked in the power supply system's relay protection devices, data signal labels and other levels. Let's talk about the principle of voltage transformer and current transformer with the guys today!

The key structure and principle of voltage transformer is similar to that of transformer. The primary winding of the voltage transformer has more turns and is connected to the high voltage side under test, while the number of secondary windings is less, and the secondary load is relatively stable. The accurate measurement when connected to high impedance is only for meters and automotive relays. The working voltage winding, therefore, when everything is in normal operation, the voltage transformer is close to the full load condition. The rated current of the primary and secondary windings of the voltage transformer is called the rated value transformation ratio of the voltage transformer.

The volume of the voltage transformer is small, and its load is generally very small and stable. Therefore, the primary side of the voltage transformer can be regarded as a constant voltage source, and most of it will not be harmed by the secondary load. The transformer is different. Its primary working voltage is greatly affected by the secondary load. The impedance of the operating voltage electromagnetic coil of the detection instrument and the car relay connected to the secondary side is very large. When everything is in normal operation, the voltage transformer is basically operating under full load.

Current transformer is a kind of current transformer, the principle of current transformer. Only its secondary winding is only connected in series with the current winding of the instrument panel and automobile relay.

The primary winding of the current transformer is connected in series in the power circuit and the number of turns of the coil is very small. The current in the primary winding is completely based on the load current of the power circuit under test and is not related to the size of the secondary current. The transformer is the reverse, the size of the primary current changes with the transformation of the secondary current. The instrument panel connected to the secondary winding of the current transformer and the current winding of the automobile relay have little impedance, so it operates close to a short-circuit fault under all normal conditions. Generally, the low-voltage side of the transformer is not allowed to operate under short-circuit faults.

The primary working voltage of the transformer determines the main magnetic flux in the transformer core, and the main magnetic flux determines the secondary potential difference. Therefore, the secondary working voltage will not change, and the secondary potential difference will basically not change. The current transformer is not the case, when the impedance in the secondary circuit changes, it will also harm the secondary potential difference. Under a certain value of the primary current effect, the size of the magnetic induction secondary current is determined by the impedance in the secondary circuit.

When the secondary impedance is large, the secondary current is small, and the primary current used to balance the secondary current is small, and the excitation current As it increases, the secondary potential difference becomes higher. On the contrary, the secondary impedance hour, the secondary current of magnetic induction exceeds the part of the primary current used to balance the secondary current, and the excitation current decreases, and the secondary potential difference is also low.

Most of the magnetic flux caused by the primary current of the current transformer is balanced by the secondary current. If the secondary leads, the primary current will be all used for the excitation current, so that the transformer core will be saturated, and high voltage will be induced in the secondary magnetic field and the transformer core will overheat. Therefore, the secondary current transformer is not allowed to lead the way.

Nanocrystalline Cores Make Tough Issues Easier

 Nanocrystalline Cores Turn Tough Issues Easy

Tough problems have been solved when ferrite cores were replaced by nanocrystalline soft magnetic cores.

(1) Noise

In the process of working with electrical appliances, noise is mainly generated in the following two aspects:

1. Due to the magnetostriction index of the raw material itself, such as ferrite, noise always occurs in the application. And because of the different composition of nanocrystalines, the magnetostriction index is also different. For example, as output transformer, voltage transformer, common-mode filter, etc., the use of iron-based nanocrystalline ribbons reduces the magnetostrictive index. According to customer applications, the noise problem has been greatly improved.

2. The problem at the rectifier circuit level, the direct current in the power supply circuit causes the magnetic induction intensity of the transformer core to increase, thereby causing noise. Tests have proved that noise is directly proportional to the intensity of magnetic induction at work. SAT Amorphous has adopted corresponding countermeasures on the power circuit, so that the nanocrystalline transformer core produced has few noise problems for many years.

(2) The problem of ductility

Before technical improvements, the ductility of the nanocrystalline transformer core was manifested, which was not only a hot potato for simple installation, but also easily caused a short-circuit failure of the power circuit. SAT Amorphous has undergone many years of practical activities, scientific research, adjustment of ingredients and processing technology, the ductility of nanocrystalline ribbons has been greatly improved. After the composition is adjusted, the flexibility of the strip has been significantly improved. In addition, in the processing technology of manufacturing transformer cores, the operation of filling the transformer cores with glue not only promotes the overall strength of the transformer cores, but also fixes the interlayer gaps of the ribbons, making it difficult to cause common problems. Therefore, while eliminating the ductility problem of the transformer core, the working noise is also reduced.

(3) Consistency issues

Consistency is related to the scale of manufacturing operations and the capacity of production equipment. In terms of quality, 1,000 tons of amorphous ribbons can be sprayed by 1,000-ton machine and 100-ton machine. Obviously, the products from the former machine has better consistency in composition and magnetic energy than the latter one. Therefore, a large scale of manufacturing and operation and a large production line equipment volume are more beneficial to consistency. SAT Amorphous has furnace and spray machine with an annual output of 1,000 tons.

(4) Application issues

Applications are usually the most concerned by customers, especially those who are cooperating for the first time and have a demand for nanocrystalline materials. In the past several years, nanocrystalline applications have become more and more common, not only for inverter welding machines, but also many electroplating equipment, intermediate frequency induction furnaces, battery charging equipment, power systems, UPS switching power supplies, X-ray film machine, switching power supplies, lasers Industries, generators and AC motor speed control switching power supplies have increased their application proportions. For example, due to the insufficient performance of ferrite core, it is necessary to use multiple ferrite cores at the same time to meet the output power. However, only one nanocrystalline transformer core is required. From the cost point of view, the price of a single ferrite core may have an advantage, and the total price of multiple transformer cores will be higher than the price of nanocrystalline transformer cores.

For more information of the nanocrystalline ribbon please click here.