Low-frequency transformers use multiple wires and are well wrapped.

2019-05-05 15:01:17 JUKE CHINA ODM OEM Transformer factory Read

Low-frequency transformers use multiple wires and are well wrapped.

Low frequency transformer

The low frequency transformer is used to propagate the signal voltage and signal power, and also achieve impedance matching between the circuits, which has an isolation effect on the direct current. There is no difference between the high frequency transformer and the low frequency transformer. However, due to the different frequencies of high frequency and low frequency, the core used in the transformer is different. Low-frequency transformers generally use high-permeability silicon steel sheets, while high-frequency transformers use high-frequency ferrite cores.

working principle

The tongue is 32 mm thick, 34 mm thick, and 96 mm wide. The maximum power is used for thicker wires. The tongue is the cross-sectional area of the EI-type transformer. It is the middle of the E-piece (inserted into the middle of the Satons transformer skeleton). The width of the inner core, that is, the width of the core tongue and the total thickness of all the E sheets inserted into the square of the transformer, that is, the stack thickness, is simply the area of the middle square of the transformer skeleton, and the sectional area of the transformer core refers to the coil The sleeved part: tongue width × stack thickness = sectional area, unit: cm2.
Low frequency transformer.jpg

The first calculation method (1) Transformer steel section: 3.2 cm*3.4cm*0.9=9.792cm2 (2) Calculate the transformer power according to the section of the silicon steel sheet: P=S/K^2=(9.79/1.25)^ 2 = 61.34 watts (take 60 watts) (3) Calculate the number of turns per volt according to the section: W = 4.5 * 105 / BmS = 4.5 * 105 / (10000 * 9.79) = 4.6 匝 / volt (4) primary coil turns :220*4.6=1012匝(5) Primary coil current: 60W/220V=0.273A(6) Primary coil wire diameter: d=0.715 =0.37(mm)(7) Secondary coil turns: 2*(51* 4.6*1.03)=2*242(匝)(1.03 is a step-down factor, two-stage 51V=2*242匝) (8) Secondary coil current: 60W/(2*51V)=0.59A(9) times Grade wire diameter: d=0.715 = 0.55 (mm) The second calculation method E-shaped iron core calculates the tongue width with the middle tongue. Calculation formula: Output power: P2 = UI Considering the loss of the transformer, the primary power: P1 = P2 / η (where η = 0.7 ~ 0.9, the general power is large) The formula for each volt is calculated: N (per volt匝)) = 4.5 × 105 / B × S (B = permeability of silicon steel sheet, generally in the 8000 ~ 12000 Gauss, good silicon steel sheet selection of large values, and vice versa. S = iron core area, the unit is cm2 If the quality of silicon steel sheet is generally 10000 Gauss, it can be simplified as: N=45/S When calculating the number of turns of the secondary winding, considering the leakage inductance of the transformer and the copper loss of the conductor, the winding allowance must be increased by 5%. There is no need to add margin to the primary. The wire diameter is determined by current: I=P/U (I=A, P=W, U=V) is selected from a wire diameter of 2.5 to 2.6 A per square millimeter. The third calculation method first needs to explain that the cross-sectional area of the transformer is the cross-sectional area of the position where the coil is clamped. If your core area (the position where the coil is clamped) is 32*34=1088 mm2=10.88 cm2 Simple calculation of a small transformer: 1. Find the number of turns per volt and the number of turns per volt = 55 / core section. For example, your core section =3.5╳1.6=5.6 square centimetre, therefore, the number of turns per volt=55/5.6=9.8匝2, find the number of coil turns primary coil n1=220╳9.8=2156匝secondary coil n2=8╳9.8╳1.05=82.32, It can be taken as the value of 1.05 in the calculation of the number of turns of the secondary coil. Considering the voltage drop 3 when there is a load, find the wire diameter. You have not specified how many volts of current you want to output? Here I assume 8V and the current is 2A. Transformer output capacity = 8 ╳ 2 = 16 volts input capacity of the transformer = transformer output capacity / 0.8 = 20 volts primary coil current I1 = 20 / 220 = 0.09 amp wire diameter d = 0.8 √ I primary coil wire diameter d1 =0.8√I1=0.8√0.09=0.24mm secondary coil wire diameter d2=0.8√I2=0.8√2=1.13mm Pay attention to interlayer voltage insulation and lead-out insulation problem.
Low-frequency transformers use multiple lines and are not good enough

1. The use of multiple strands in the power transformer is mainly to solve the problem that the single-strand enameled wire is too thick to be easily wound.

2. The use of multiple strands in high-IF transformers is mainly to solve the problem of electromagnetic leakage caused by high frequency.

3. The use of multiple strands in the audio transformer is mainly to solve the balance problem in the amplifier circuit.
Low frequency transformer winding method

1. Material confirmation

Confirmation of 1.1 Bobbin specifications.

1.2 Confirm that Bobbin is complete: there must be no damage or cracks.

1.3 Bobbin is correctly inserted into the fixture. Bobbin with PIN is generally marked as 1 foot (the angle is Pin1). If the drawing is not specified, the horizontal Bobbin1 foot is facing the machine, and the vertical BobbinPin is facing the person. In the case of Bobbin without Pin, the number of primary and secondary lead wires must be confirmed first, and the line of sight is convenient for the line to confirm the pin position.

1.4 The package of acetate cloth should be packaged according to the requirements of the engineering drawings, close to the sides of Bobbin, and then the wire is wound on the designated Pin (or the first hook line), and the winding should be within the specified range. Winding

2, winding method.

2.1 Secondary winding: Arranged neatly to a certain extent. When the uppermost layer is reached, the wiring is disordered and uneven. This is the roughest winding method in the winding, that is, arbitrary winding (as shown below)
Low frequency transformer winding method.jpg

2.2 The primary winding is arranged neatly to a certain extent. When the uppermost layer is reached, the wiring is disordered and uneven, which is the roughest winding method in the winding. (As shown below)
Low frequency transformer winding method.jpg

3. Precautions.

3.1 When the transformer is wound, the winding method is unified. In addition, the vertical Bobbin foot must be facing outward, and the horizontal Bobbin first foot is facing outward. The position of the winding point and the cut-off point must meet the requirements on the engineering drawing. And the winding direction of each group needs to be consistent with the direction of the main coil, and there is no possibility that the winding direction of any group is opposite to the main coil due to the convenience of operation, and the winding order L1, L2, ... Ln. It is also not allowed to adjust the tone at will, and it is not possible to change the winding point of the winding point and the cutting point. (Note: This item stipulates that the IPQC dismantling inspection needs to be checked for its execution.) 3.2 The enameled wire of the primary wire diameter above AWG#32 (including AWG#32, #33, #34...), its access The foot at the line must be wrapped around the line for three times. The end of the strand should be completely wrapped in the tape to avoid poor pressure due to short circuit between the wire and the silicon steel sheet.

3.2AWG#28 to AWG#32 enameled wire shall have a buffer section when it is wrapped around the foot to avoid disconnection. (Note: This item requires IPQC dismantling inspection to check its implementation.)

The enameled wire above 3.3AWG#19 (inclusive) should be wrapped around the top of the Pin (at least one turn) and then pressed back down to the bottom of the Pin to ensure the cushioning effect. (As shown below)

3.4 Winding is to be flat, not to one side. The inlet and outlet wires must be insulated with acetate cloth during primary winding.

The enameled wire of 3.5AWG#28 (inclusive) or above (such as AWG#28, AWG#29, AWG#30...) must be wound by hand before winding, and then wound by a winding machine.
Low frequency transformer winding parameter problem

The formula for calculating the number of turns per volt of a commonly used small transformer is: N=10000/4.44FBS

N—number of turns per volt, F—alternating frequency (50HZ in China), B—magnetic flux density, S—core cross-sectional area

If using H23, take a B value of 1.4

10X15mm=150/100=1.5CM"

Then: N=10000/4, 4X50X1.4X1.5=21.6

22 volts per volt!

220X22=4840匝 primary coil 4840匝!

12X22=264匝Secondary coil 264匝!

Wire diameter:

120v.25a=3W

I=P/U I=3/12=0.25A 3W/220V=0.014A

Check the wire gauge AWG: secondary wire diameter: 0.32mm high-strength enamelled copper wire! Primary wire diameter: 0.07mm high strength enamelled copper wire!


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Dongguan Juke Industrial Development Co., Ltd. is a professional automation workshop production line solution provider for High frequency transformer peripheral equipment.

Juke Industry is dominated by Taiwanese technology, and all raw materials are selected and processed in strict accordance with Taiwan Standard Huai, and with the excellent technology and professional services to create maximum value for customers, and determined to become the world's high-frequency transformer automation equipment program The leading brand.
Juke Industry adheres to European standards, and its product series include: Transformer automatic inserter, ei type transformer inserter, transformer EI inserter, transformer core inserter, transformer automatic casing machine, transformer automatic core Assembly machine, (automatic core assembly + bag tape + test + wobble plate), transformer automatic winding machine, CNC winding machine, CNC coil automatic winding machine, single-axis winding machine, double-axis winding machine, more Shaft winding machine, 12-axis automatic winding machine, automatic winding + wrapping tape machine, (USB charger automatic wrapping machine), automatic rubberizing machine, semi-automatic wrapping tape machine, transformer core assembly rubberizing machine, Vacuum impregnation machine, (with single and double cylinder difference: automatic single cylinder vacuum impregnation machine, automatic double cylinder vacuum impregnation machine), automatic soldering machine and semi-automatic soldering machine (also called flip soldering machine), transformer automatic flip soldering Machine, magnetic ring inductance automatic foot machine, infrared tunnel furnace, ultraviolet curing furnace, baking line and other high-frequency transformer peripheral automation equipment, products are widely used in high and low frequency transformers, ballasts and motor factory industry. In order to meet the needs of the market, in 2008, in Yixiu District, Anqing City, Anhui Province, a group of professional and technical personnel to provide quality services to customers.

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