Winding method and comparison of interlayer shielding of high frequency transformer

It is often seen in the electronics industry that when returning goods, the quality reason is “multi-threaded”. This is really wrong to the enameled wire factory. Because the current production machines of enameled wire are single-end pay-off and single-end take-up, there is no multi-end.

The shielding layer leads a wire to be grounded, which is the reference point of potential. Conventional shielding is done between the primary and secondary windings. Whether it is the outermost layer or the inner winding shielding, you need to pay attention: when the winding is wrapped with copper foil, the copper foil overlaps the ends of the copper foil and needs to be insulated. The reason is simple: if there is no insulation, overlapping and connecting is a short-circuited coil!

A layer of non-conductive materials, such as resin, plastic, silicone rubber, PVC, etc., is evenly and hermetically wrapped around the wire to form an insulating layer to prevent the conductor from contacting the outside and causing leakage, short circuit, electric shock and other accidents. The wire is called insulation wire.

Compared with the solder wire welding method, the dip soldering method has many advantages, as follows:
First of all, in terms of welding quality, as long as the part below the surface of the tin liquid is immersed, the tin will be tinned, and the tin will be tinned 360 degrees at one time. The welding quality is very reliable. There is a large contact area between the lead wire and the aluminum enameled wire on the solder joint. Compared with the terminals), the resistance is much smaller than other places in the loop.

The conductive properties of pure metal materials are ranked. Among them, the material with the best conductivity is silver (Ag), followed by copper (Cu), after copper, it is gold (Au), and then aluminum (Al). Analyzed from the application level, silver and gold are precious metals and cannot be used in large quantities when the unit price is too high. Copper is the best choice for moderate price and good performance, and it is the main force used in the current industry. It is widely used in electrical related industries, such as enameled coils used in motors, whose internal conductors are made of copper. Although aluminum is the cheapest material among them, the difference in its electrical conductivity is an unacceptable conductor material in applications where high efficiency is the premise.

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The constant voltage transformer integrates voltage stabilization, isolation, and transformation. It has a two-way filtering function that can eliminate noise from the power grid. It has good anti-interference ability. The output is sine wave or quasi-square wave. It is an ideal stabilized power supply for precision electronic instruments, microcomputers and numerical control equipment. There is a “day”-shaped iron core in the constant voltage transformer, the primary coil is in one window, and the secondary coil and resonant coil are in the other window. The resonant coil is connected to a resonant circuit whose resonant frequency is close to the frequency of the power supply.
When the primary power supply is connected, the resonant circuit oscillates to shallowly saturate the secondary iron core and form a constant alternating magnetic field. The magnetic induction intensity is within a certain range and is basically not affected by the input voltage change. The induced electromotive force remains unchanged. In this case, the primary input current only plays a role in supplementing energy.

Dry-type transformers are widely used in local lighting, high-rise buildings, airports, terminal CNC machinery equipment and other places. Simply put, dry-type transformers refer to transformers whose cores and windings are not immersed in insulating oil.
Cooling methods are divided into natural air cooling (AN) and forced air cooling (AF). When natural air cooling, the transformer can run continuously for a long time under the rated capacity. When forced air cooling, the output capacity of the transformer can be increased by 50%. It is suitable for intermittent overload operation or emergency accident overload operation; due to the large increase in load loss and impedance voltage during overload, it is in a non-economic operation state, so it should not be kept in continuous overload operation for a long time

Reduce the DC losses of the windings:
1. Use conductors with low resistivity to make transformers, generally copper enameled wires are used, and copper-clad aluminum enameled wires or aluminum enameled wires are not used as much as possible.
2. When the area of the transformer window allows, try to use an enameled wire with a larger equivalent cross-sectional area (a single wire should not exceed the penetration depth, which will be analyzed later)
3. Appropriately reduce the number of turns of the winding (will increase the iron loss), use with caution

my country is the world’s largest enameled wire country, accounting for about half of the world’s output. According to statistics, my country’s enameled wire output in 2020 is about 1.76 million tons, a year-on-year increase of 2.33%.

Polyester acid/polyamide composite enameled round copper wire
1. Model: Q(ZY/X)-1/180 Q(ZY/X)-2/180
2. Temperature resistance grade: H grade (temperature index 180)
3. Production specifications: ¦µ0.20-¦µ1.50mm
4. Product implementation standard: GB 6109.10 IEC 317-22 (1990)
5. Main performance: The product has high thermal shock and small surface friction coefficient.
6. use: suitable for long-term working under high temperature motors, coil windings of instrument communication equipment, especially suitable for high-speed winding occasions.

Permanent magnet brushed DC motor: The coil wound by the enameled wire is the armature winding of the motor. The armature winding converts electricity into a magnetic field, and then interacts with the magnetic field of the permanent magnet. The attraction and repulsion between the two magnetic poles drive the motor Rotate.

The biggest difference between enameled aluminum wire and enameled copper wire for single-phase induction motors is also caused by the poor conductivity of aluminum. Therefore, the wire diameter of enameled copper wire has to be reduced to 0.12. The same motor specifications as enameled aluminum wire can be reached by about mm. On the contrary, if the single-phase induction motor that originally used enameled copper wire is changed to enameled aluminum wire, the wire diameter must be somewhat larger. To increase, it can reach the specifications required by the original motor. Therefore, the motor will need more space to accommodate the increased wire diameter, but this more space is often the most difficult to provide among the motors.

Why Copper Wire Is the Metal That Fits the Needs of Electrical Wire Manufacturing Industry
Key Properties That Makes Copper the Ideal Choice
Favorable Chemical Properties
Can Withstand Changes in Temperatures

The electromagnetic coil is built by using the magnetic field around the wire, winding it into a spiral to strengthen the magnetic field, that is, using the smallest space to achieve the highest magnetic field strength, and replacing the ordinary wire with a wire covered with a layer of insulating paint is also to save space .

The insulating paint used in the motor can be divided into six types according to its purpose: impregnating paint, enameled wire paint, covering paint, silicon steel sheet paint, anti-corona paint and surface anti-rust paint.

Winding Enameled Wires used for Dry-type transformers which are widely used in local lighting, high-rise buildings, airports, terminal CNC machinery equipment and other places. Simply put, dry-type transformers refer to transformers whose cores and windings are not immersed in insulating oil.

Inductors are components that can convert electrical energy into magnetic energy and store it. The structure of the inductor is similar to that of a transformer, but it has only one winding. The inductor has a certain inductance, it only hinders the change of current. If the inductor is in a state where no current is flowing, it will try to block the current from flowing through it when the circuit is on; if the inductor is in a state where current is flowing, it will try to maintain the current when the circuit is off. Inductors are also called chokes, reactors, and dynamic reactors.

The coil is wound around an insulating tube by a wire, and the wires are insulated from each other. The insulating tube can be hollow, or it can contain an iron core or a magnetic powder core. The inductance of the coil is represented by L, and the units are Henry (H), millihenry (mH), microhenry (¦ÌH), 1H=10^3mH=10^6¦ÌH.

Due to its own characteristics, hollow coils have been widely used in voice coils in the electro-acoustic industry, deflection coils in precision instruments, combined coils in micro motors, and micro coils in sensors. Self-adhesive enameled wire has increasingly become the main wire type used in the coil winding process due to its excellent heat resistance, insulation, adhesion durability, easy molding, and simple winding process

Traverse refers to the material used for wire and cable, and also refers to wire in industry. It is generally made of copper or aluminum, and it is also made of silver wire (good electrical conductivity and thermal conductivity), which is used to reduce electrical current or conduct heat.

Compared with ordinary round enameled wire windings, flat enameled wire windings have the characteristics of higher energy density, higher motor efficiency, corona resistance, high insulation strength, zero pinholes, and smooth surface under the same volume, which can replace ordinary round enameled wires. Used in new energy vehicle motors.

Aluminum wire is easy to oxidize in the air, forming a layer of oxide on its surface. In addition, aluminum is less hard than copper, which will greatly increase the contact resistance between the aluminum wire and the copper wire.

As one of the core three-electric systems of new energy vehicles, electric motors account for 5-10% of the value of the entire vehicle. Among the top 15 new energy vehicle sales in the first half of 2021, the penetration rate of flat wire motors has increased significantly to 27%. The industry predicts that in 2025, the proportion of flat wires in the drive motors of new energy vehicles will exceed 80%.