Why Y capacitor capacity can not be too large

The Y capacitor is a capacitor that is connected between the two lines of the power line and the ground (LE, NE). The medium is ceramic, which is a kind of ceramic capacitor. The Y capacitor and the high voltage ceramic capacitor are different. The Y capacitor is a safety capacitor. After the failure, it will not cause electric shock and will not endanger the personal injury. Since the Y capacitor is so good, why not make the capacity bigger and make the application more extensive? In fact, this is for a reason.

The capacity of the Y capacitor should be no more than 0.1uF. The Y capacity of most manufacturers produces Y700 with a capacity of 4700pF and Y2 with a capacity of 10000pF. As for why there is no Y capacitor with a larger value, the main reasons are:

1. The current production process is limited. Because the Y capacitor is different from the ordinary high-voltage ceramic capacitor, it has to withstand higher pulse voltage, and there is no risk after the capacitor fails. Therefore, the ceramic medium should not be too thin, resulting in a small capacitance. .

2, the scope of application, Y capacitor is mostly used to suppress the electromagnetic interference of the power supply, so it is often connected between the power line and the ground. The power supply is 50Hz AC in China, and the capacitor has the ability to block DC communication. Therefore, after the power is turned on, there is a certain current passing through the Y capacitor. The larger the capacitance value, the larger the current flowing, the current is called Leakage current.

At present, there is a leakage current requirement in the electrical equipment. The machine operating in the tropics requires that the earth leakage current should not exceed 0.7 mA. When working in a temperate machine, the earth leakage current should not exceed 0.35 mA. Otherwise, there is a hidden danger. The Y capacitor is not required to be too large. Y capacitor capacity can not be large, but the current production process limitations, I believe that the future technology can produce a large capacity of Y capacitors, the current technology is still a guarantee, to ensure large capacity, purchase capacitors Looking for a regular capacitor manufacturer.

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