1, taking plastic-clad copper-core transformer as an example. Generally, 300w power weighs about 3 kg, and 500w power weighs about 5 kg. If the iron shell is used to reach the above weight, please choose carefully.

2. Look at the price. The futures price of copper in the international market is around 50,000 yuan/ton, which is roughly equivalent to 50 yuan/kg. If it is wound with copper core, the price of 300w transformer is lower than 100 yuan, and the price of 500w transformer is lower than that of 200 yuan, which is suspected of fraud. So choose carefully.

3. Look at the temperature. The transformer wound with copper core will be slightly heated when working. The temperature is comparable to human body temperature, and it only feels warm. If it feels hot, it is usually wrapped with aluminum core. Please choose carefully.

Advantages of aluminum core cable:

1. Oxidation resistance and corrosion resistance: aluminum reacts with oxygen in the air to form an oxide film, which can prevent further oxidation, so aluminum conductor is an essential material for high voltage, large cross-section and long-span overhead transmission. Although aluminum core cable is cheaper, copper core cable has outstanding advantages in cable power supply, especially in the field of underground cable power supply. The underground power supply of copper core cable has the characteristics of low accident rate, corrosion resistance, high reliability and convenient construction and maintenance.

2. The cable is very light: the weight of aluminum core cable is 40% of that of copper core cable, and the construction and transportation costs are low.

3. Cheap price: The price of copper rod is 3.5 times that of aluminum rod, and the proportion of copper is 3.3 times that of aluminum, so aluminum core cable is much cheaper than copper core cable, which is suitable for low-demand projects or temporary electricity consumption. Summary: This is also the reason why copper cables are mainly used for underground power supply in China at present.

Advantages of copper core cable:

1. High strength: The allowable stress of copper at room temperature is 7-28% higher than that of aluminum. Especially the stress at high temperature, the difference between them is even further.

2. Anti-fatigue: aluminum is easy to break after repeated bending, but copper is not easy. In terms of elastic index, copper is also about 1.7~ 1.8 times higher than aluminum.

3. Convenient construction: ① The copper core is flexible, with small allowable bending radius, convenient turning and easy pipe threading; (2) The copper core is fatigue-resistant, difficult to break after repeated bending, and convenient for wiring; (3) The copper core has high mechanical strength and can bear large mechanical tension, which brings great convenience to construction and laying, and also creates conditions for mechanized construction.

4. Good stability and corrosion resistance: copper core is resistant to oxidation corrosion, while aluminum core is easy to oxidation corrosion.

5. Large current carrying capacity: Due to the low resistivity, the allowable current carrying capacity (the maximum current that can pass) of copper-core cable with the same cross section is about 30% higher than that of aluminum-core cable.

6. Low resistivity: The resistivity of aluminum core cable is about 1.68 times higher than that of copper core cable.

7. Good ductility: the ductility of copper alloy is 20~40%, that of electrical copper is above 30%, and that of aluminum alloy is only 18%.

8. Oxidation resistance and corrosion resistance: The joint performance of copper core cable is stable and will not cause accidents due to oxidation. When the connector of aluminum core cable is unstable, the contact resistance will increase due to oxidation, which will lead to accidents. So the accident rate is much higher than that of copper core cable.

9. Low power consumption: Because of the low resistivity of copper, compared with aluminum cable, the power consumption of copper cable is low, which is obvious. This is conducive to improving the utilization rate of power generation and protecting the environment.

10. Low heating temperature: under the same current, the heating value of copper-core cable with the same cross section is much smaller than that of aluminum-core cable, and it is safer to run.

1 1. Low voltage loss: Due to the low resistivity of copper core cable, under the condition that the same current flows in the same section. The pressure drop of copper core cable is small. Therefore, the same transmission distance can ensure higher voltage quality; In other words, under the condition of allowable voltage drop, the copper core cable can reach a long distance, that is, the power supply coverage area is large, which is beneficial to network planning and reduces the number of power supply points.