How to choose the specification and model of rectifier?
Publisher: Administrator Date：2021-03-05
We often encounter users, especially those who are new to the industry, who are very entangled in how to choose the specifications and models of the rectifier. If the size of the rectifier is selected, the capital appears to be wasted. If the size is small, it may be satisfied in production. Can't meet the requirements of production. When selecting a model, it is actually a matter of selecting voltage and current. How to determine the voltage is very simple, and it is related to the product, the conductivity of the plating solution, the cross-sectional area and the length of the copper bar, and I will not elaborate here.
Mainly how to determine the current size:
1. First of all, what is the upper limit of the actual current density of your product? Here, we usually use the letter J to indicate current density. In the industry, the general current density unit, we use ASD (ampere/square decimetre) or ASF (ampere/square foot) where: 1 ASD = 9.29 ASF
2. What is the surface area of your product (the electroplating area immersed in the plating solution)? Generally expressed by S, unit: square decimetre (dm2)
3. If it is hanging bottom, then count how many products are hanging next, such as N;
4. Then, the maximum required current is J*S*N
5. In general rectifier manufacturers, when designing products, the margin of the design capacity will not be too large. For example, 12V1000A, most rectifier manufacturers will design the upper limit of 1000A. In other words, the upper limit output current of this rectifier is 1000A. If it works under full load for a long time, the aging speed of electronic components will be accelerated, and their service life will be reduced. Therefore, we recommend users to reserve 20% of the margin for Yourself.
6. According to the following formula:
The rated output current of the purchased rectifier = the maximum current required by the user ÷ the surplus coefficient (usually 0.7-0.8)
The surplus coefficient of 0.7-0.8 can be determined by users.
When the funds are sufficient, it is better to be smaller, then the heat generation inside the rectifier will be smaller and the service life will be longer;
When the funds are tight, it is better to be larger, then the internal heat generation of the rectifier will be greater and the service life will be low;
But this surplus coefficient is not recommended to be greater than 0.8
For example, if the maximum current required by the user is 3000A,
Then, the recommended rectifier rated output current=3000/0.75=4000A, we can choose 4000A.
Of course, if the funds are sufficient, it will be better to choose a model above 4000A, which has a longer service life and a lower failure rate;
7. Other influences on the selection of models:
A. Whether it is an air-cooled or a water-cooled rectifier, the choice of the output copper bar or DC cable connected to the cathode and anode is also a crucial link. If the copper bar or DC cable is wrongly selected, it will inevitably be A large amount of heat is generated. If the heat is severe, the copper bar will become red and cannot be touched by the hand. Such heat will inevitably be transmitted into the rectifier through the cathode and anode, which will greatly affect the performance and life of the rectifier. (For the knowledge of how to choose the size of copper bars or cables, please refer to "How to choose the size of copper bars")
B. Use environment:
Air-cooled rectifier: If it is an air-cooled rectifier, the rectifier will have requirements for the temperature and relative humidity of the environment in which it is used. Generally, the ambient temperature of the rectifier is required to be in a ventilated environment between 0-35 degrees, and the relative humidity is between 15-85%;
The higher the operating environment temperature, the worse the heat dissipation effect of the air-cooled rectifier, so that the heat inside the machine will accumulate more and more, which will cause the internal temperature to become higher and higher and cause malfunctions.
In addition, if the relative humidity is too high, water molecules in the air will accumulate into water droplets inside the machine or on the wires, which will eventually form a short circuit or leakage, which will bring hidden dangers to the safety of use;
Water-cooled rectifier: If it is a water-cooled rectifier, in addition to the requirements for water temperature, there will also be requirements for water quality. If the water temperature is too high, the heat inside the rectifier cannot be brought out, causing the internal temperature to become higher and higher, causing malfunction or protection;
At the same time, the requirements for water quality: the first is pure water; the second is to seal circulating water. Do not use an open water tower cooling method, because during the water tower cooling process, dust in the air will accumulate in the water. Long-term use will inevitably block the internal pipes of the water cooler and cause malfunctions. Pure water must also be produced by a pure water machine. Tap water cannot be used. Because most of the tap water in China is not direct drinking water, the water will contain various microorganisms. Long-term use will easily cause microorganisms such as moss to accumulate in the pipeline. In the inner wall, heat dissipation failure is caused.