According to IEC 60384-14. capacitors are classified as X-capacitors and Y-capacitors.
X Capacitor is the capacitor that spans between L-N, while Y Capacitor is the capacitor that spans between L-G/N-G. Where L stands for Line, N stands for Neutral and G stands for Ground.
X capacitors are divided into three classes, X1. X2 and X3. the main difference is the difference in high-voltage resistance; X1 capacitors have a high-voltage resistance of more than 2.5 kV and less than or equal to 4 kV, X2 capacitors have a high-voltage resistance of less than or equal to 2.5 kV, and X3 capacitors have a high-voltage resistance of less than or equal to 1.2 kV.
Y capacitors are also divided into four grades, Y1. Y2. Y3 and Y4. the main difference lies in the different high-voltage resistance, Y1 capacitor's high-voltage resistance is more than 8 kV, Y2 capacitor's high-voltage resistance is more than 5 kV, Y3 capacitor does not have specific high-voltage resistance requirements, and Y4 capacitor's high-voltage resistance is more than 2.5 kV.
The X and Y capacitors are safety capacitors used in power filters to filter the power supply. They filter common mode interference and differential mode interference respectively. Safety-compliant capacitors are meant to be used in situations where failure of the capacitor will not result in an electric shock and will not endanger personal safety.
The safety level of safety-gauge capacitors is based on the permissible peak pulse voltage and overvoltage level for the application. x1 capacitors have a safety level of III, with a permissible peak pulse voltage greater than 2.5kV and not exceeding 4.0kV; x2 capacitors have a safety level of II, with a permissible peak pulse voltage of not exceeding 2.5kV; and x3 capacitors do not have a specific safety level requirement.
For Y capacitors, the safety level is determined according to the type of insulation and the rated voltage range. Y1 capacitors use double insulation or reinforced insulation, and the rated voltage range is greater than or equal to 250V; Y2 capacitors use basic insulation or additional insulation, and the rated voltage range is greater than or equal to 150V and not exceeding 250V; Y3 capacitors use basic insulation or additional insulation, and the rated voltage range is greater than or equal to 150V and not exceeding 250V; Y3 capacitors use basic insulation or additional insulation, and the rated voltage range is greater than or equal to 150V and not exceeding 250V. equal to 150V and not exceeding 250V; Y4 capacitor adopts basic insulation or additional insulation, the rated voltage range is less than 150V.
It should be noted that the capacitance of the Y-capacitor must be limited for the purpose of controlling the magnitude of the leakage current and the impact on the EMC performance of the system. According to GJB151. the capacity of Y capacitor should be no more than 0.1 uF. In addition, Y capacitors are required to meet the corresponding grid voltage withstand voltage in addition to sufficient safety margins in electrical and mechanical properties to avoid breakdown short-circuit phenomenon under extreme harsh environmental conditions. Therefore, the voltage withstand performance of Y capacitors is of great significance for the protection of personal safety.
In the filter circuit, there is X capacitor is connected across the L-N line, while Y capacitor is connected across the N-G line. In safety standards, according to the pulse voltage can be divided into X1. X2. X3 capacitors, according to the insulation level can be divided into Y1. Y2. Y3 capacitors. These classifications are not according to the material, but according to different parameters.
As for the safety standards there may be some differences between different countries, but the rated voltage is usually only two kinds, 250V and 400V. The safety capacitors produced by major manufacturers have to meet the requirements of these safety standards. A safety-gauge capacitor can meet the requirements of a Y capacitor as well as an X capacitor. For this reason, some safety capacitors are labelled with markings such as X1Y1 and X1Y2.
When a capacitor is connected between the fire wire and the zero wire, the X capacitor is used; and when a capacitor is connected between the fire wire and the earth wire, the Y capacitor is used. As the direct access capacitor between the fire wire and the zero wire will be affected by voltage peaks, in order to avoid short circuits, the focus is on the voltage withstand level, while there is no specific limit on the capacitance value.
When a capacitor is connected directly from the firewire to the earth wire, the issue of leakage safety is involved, so the focus is on the insulation level.
UF Capacitors supply X1Y1 250VAC and 400VAC,X1Y2 500VAC, film box type cap X2 capacitor 270VAC，305VAC，310VAC.
More to see, please visit: www.ufcapacitors.com
Or send RFQ to our sales: carey@ufcapacitors.com