How to Select High-Quality Reactors

Therefore, some industry insiders vividly refer to the reactor as the close companion of the capacitor for maintaining its strength. Our high-quality reactors are basically determined by five key metrics:
1.Low temperature rise
2.Low noise
3.High overcurrent capacity
4.High linearity
5.High insulation grade

The core of the reactor
The quality of all products is guaranteed by raw materials, processes, and equipment. The reactor is no exception. These five indicators are mainly determined by two major materials and the manufacturing process. One is the core, and the other is the winding. The price is also mainly determined by these two factors.
Why is this the case? Because the reactor is a large metal lump, mainly composed of metal materials. And the first important component in metal materials is the core, because the core is the main channel of the magnetic circuit of the reactor. Without this magnetic path, the reactor is useless. Therefore, the quality of the core directly or indirectly determines the performance of the reactor.
So a good core can give the reactor the characteristics of low noise, low temperature rise, low loss, and high electrical performance. The core is made of silicon steel sheets, and it is then vacuum impregnated later.
So we need to focus on two points: one is the selection of silicon steel sheets, and the other is the manufacturing process. The silicon steel sheets must be selected from large factories (such as Baosteel, Wuhan Iron and Steel), so as to ensure that the provided are high-quality, low-loss cold-rolled silicon steel sheets. Good cold-rolled silicon steel has good magnetic permeability, and good magnetic permeability means lower loss, lower heat generation, and less impact on the reactor. Therefore, an electric reactor made with good materials will be more stable. At the same time, the noise will be lower because the noise comes from the hysteresis contraction of the silicon steel sheets.
At the same time, high-quality silicon steel sheets have smaller burrs when cut. Smaller burrs are more visually appealing. From an electrical perspective, burrs are conductive and can damage insulating materials. Therefore, better silicon steel sheets can ensure higher insulation performance.
In addition, the core is made by layering the silicon steel sheets one by one. We must pay attention to how the silicon steel sheets are layered. If the layering is not done properly, even the best materials will not show their advantages. First, the layers must be stacked neatly, and the gaps must be good to ensure the consistency of the product.
This process, if done manually, will cause uneven stress on the silicon steel sheets, and the number of silicon steel sheets in each iron core may also be inconsistent and not neat. Therefore, it must be machine-stacked and pressed. If this process is not done well, the appearance will be affected in terms of aesthetics, and the magnetic permeability will be affected in terms of performance.

The wire material of the reactor
After introducing the core, let's talk about the material of the wire. This is the most frequently asked question by customers during our sales process. Our reactors are also named based on the wire material. From the type perspective, there are two categories: wire-wound reactors and foil-wound reactors. From the material perspective: aluminum reactors, copper reactors. Here, we take the copper wire-wound as an example to illustrate.
Let's take a look at the comparison between copper and aluminum. Compared to aluminum, copper has a higher density and better current conductivity, which is what we call good electrical conductivity. The better the electrical conductivity, the less heat generation, lower temperature rise, and of course, lower loss, and a longer service life. Therefore, copper is superior to aluminum.
For civilian-level projects, with specialized design, using aluminum material is also possible. For industrial-level projects with large load variations, copper material must be used.
Even for copper, there are red copper (brass) and yellow copper distinctions. Red copper is purer copper, and yellow copper is made by processing copper and zinc. Red copper has better conductivity and heat conductivity, so even copper has differences.
In conclusion, from the performance perspective, red copper > yellow copper > aluminum, and from the cost perspective, it is also red copper > yellow copper > aluminum. Therefore, when purchasing, we cannot simply compare prices. Of course, a higher price does not necessarily mean better quality. Because during the sales process, business factors will be involved. So we must look at the material.
Since the surface of our wire materials all need to be treated with paint (to achieve insulation purposes, and the paint treatment process also has its own requirements, we won't go into detail here), it is made into enameled wire, and it is not easy to distinguish from the outside. So many manufacturers take advantage of this loophole to deceive customers by using inferior products instead of good ones. Using aluminum instead of copper, and even worse, using sprayed wire or silk-wrapped wire, the insulation layer is prone to fall off, and the heat resistance level is low.
Here is a very simple and crude method: just look at the copper terminals or use a small knife to scratch it, you can tell the difference. Of course, we try not to do this. When cooperating, we will try to find professional and honest factories for on-site inspections.

Transformer winding process
Now let's talk about how to wind the coils. There are two manufacturing processes here: one is manual tapping winding, and the other is machine winding. In terms of quality, machine winding is superior because manual tapping can damage the insulation layer and is not reliable.
After the coils are wound properly, we need to make the copper terminals (the connection lines between the wire and the outside). The process of welding the copper terminals is very crucial. If it is not secure, such as poor soldering or detachment, it can cause damage and even lead to a fire.
Also, we all know that the transformer is a device with very high heat generation. Therefore, there must be an overheating protection measure. When choosing a transformer, this point must be noted. After all, safety is no trivial matter.
The common practice is: on a small terminal on the transformer, there is a pre-installed normally closed temperature control sensor (normally closed at 120℃) that can achieve the overheat protection function. This terminal is a normally closed contact. When the temperature of the transformer is too high, this contact opens, and this contact can be used to cut off the control circuit to allow the transformer to exit the system operation, thereby ensuring the safety of the transformer and the equipment in the downstream branch.

Other concerns regarding reactors
Apart from the main materials and manufacturing processes mentioned above, other auxiliary materials such as frames, insulating paper, epoxy boards and materials also need to have good insulation properties. These factors will directly or indirectly affect the quality of the reactor. Some manufacturers, in an attempt to reduce costs, may purchase inferior materials.
The final process is dip coating. We must ensure 100% immersion to improve product performance and reduce noise.