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Can high-frequency transformer triple insulated wire be replaced with casing?
Mar 26, 2018

Can high-frequency transformer triple insulated wire be replaced with casing?


The high-frequency transformer triple insulated wire is a high-performance insulated wire. The wire has three insulating layers with a core wire in the middle. The first layer is a golden yellow polyamine film with a thickness of several micrometers but can withstand 3KV. The pulsed high voltage, the second layer is a highly insulating paint coating, the third layer is a transparent glass fiber layer, the total thickness of the insulating layer is only 20-100um, its advantage is high dielectric strength, between any two layers Can withstand the safety voltage of AC 3000V, current density.


The following points should be noted when using three layers of insulated wire:


1. The storage condition of the three-layer insulated wire is that the ambient temperature is -25~30 degrees Celsius, the relative humidity is 5%~75%, and the storage period is one year. It is forbidden to store three layers of insulated wire under high temperature, high humidity, direct sunlight and dust. For the three-layered insulated wire that exceeds the storage period, the insulation breakdown voltage, withstand voltage, and winding test must be re-tested before use.


2. The following precautions must be observed in the winding: The three-layered insulated wire is reinforced by insulation. If the film is severely deformed or damaged due to mechanical stress or thermal stress, safety standards cannot be guaranteed; there must be no burrs on the transformer skeleton, and the corners of the contact wires should be rounded (chamfering), and the inner diameter of the outlet nozzle should be 2 to 3 times the outer diameter of the wire; cut the end of the wire very sharp, do not close to the wire coating.


3. When peeling the film, special equipment such as a three-layer insulated wire stripping machine and an adjustable stripping film machine are used. It is characterized by peeling while melting the film, so it does not damage the wire. If an ordinary wire stripping machine is used to strip the insulation coating, the wire may be attenuated or even pulled.


4. There are two devices for welding three-layer insulated wires. One is a stationary solder tank, suitable for welding three-layer insulated wire below 4.0mm. When soldering horizontal movement in the solder tank and vibrating the coil bobbin, the welding work can be completed in a short time. Another welding device is an air-cooled jet solder tank, which can simultaneously perform the welding of multiple coil bobbins and is suitable for mass production.



For some high-frequency transformers due to the small skeleton, the transformer manufacturer's technicians recommend using a bushing instead of a set of three-layered insulated wires. Is the volume after the casing smaller than the volume of the three-layer insulated wire?


Answer one: First we must understand the development of three-layered insulated wire. When there is no three-layered insulated wire, the primary and secondary wires are made of enameled wire, but we must add a retaining wall to meet the safety distance of 6.4mm, and later we have a three-layer insulated wire. The three-layer insulated wire withstands 4000V, so the cancelled wall is insulated with three layers. The casing is only responsible for isolation. Of course, if you put the entire winding wire on the casing, the above will not be established.


Answer 2: The transformer manufacturer's proposal should be just the inlet and outlet bushings. With enameled wire, the thickness will be much smaller throughout the day. In fact, it is mainly to see how your safety requirements are required. It is possible to use enameled wire instead, if the inlet and outlet lines and edges are isolated. it is also fine.


Answer 3: After the casing, the volume of course becomes much larger. The ideal solution is: After you have wound a group, thicken it with insulating yellow wax (or after a round of electrical insulation tape) in another group. Than you use the casing to save a lot of volume. I personally think that it is best to use thick yellow wax, because it is resistant to high temperatures and pressure, and has very good insulation properties. The temperature is normally used within 24 hours for continuous use within 80 degrees. No problem occurs. With electrical insulating tape, high temperature resistance is not acceptable and it is easy to damage. Drop it.


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