Safety Standard Certified Capacitors

 

In industrial, safety capacitors are capacitors that meet safety regulations and have passed the safety test.

 

Safety capacitors can be used for power supply noise suppression circuit in cross connection and bypass.It is a primary and secondary coupling X/Y capacitor used as AC line filter and switching power supply and AC converter.These safety capacitors are also known by other names,including EMI/RFI suppression capacitors and AC line filter safety capacitors.

 

EMI stands for electromagnetic interference.

 

RFI stands for radio-frequency interference, RFI is simply higher-frequency EMI.

 

 

Safety capacitors have a wide range of applications and are used in a large number of power products, adapters, motors and other products.

 

Safety Capacitor Classification

 

A safety capacitor can be subdivided into an X-capacitor and a Y-capacitor.Class-X and Class-Y capacitors are classified according to:

 

their peak voltage/rated voltage

the peak impulse voltage that they can safely withstand.

 

How to Select Safety Capacitors

X capacitor is connected across the power line between the two lines, that is, "L-N" between the X capacitor can suppress the differential mode interference, usually take the metallised film capacitors, capacitance is uF level. x capacitor most of the square, that is, similar to the shape of the box, the surface of the generally marked with the safety certification mark, the word voltage resistance rely on the standard and other information(generally have AC300V or AC275V) . rely on the standard and other information. x capacitor is a kind of CBB capacitor, but not every kind of CBB capacitor can do x capacitor must meet the safety standards.

 

Y capacitors are usually ceramic capacitors, generally appear in teams, most of them are flat round appearance, blue in colour, able to suppress common mode interference, Y capacitance is nF level. Based on the constraints of leakage current, Y capacitance can not be very large, most of Y capacitors are suitable for isolation occasions, according to the IEC standard, the minimum electrical gap of Y1 products is 8.0㎜, and the electrical gap of Y2 products is not less than 6.3㎜, as an isolation product, the safety distance should be enough to avoid the phenomenon of high-voltage energised arc pulling.

 

1、Voltage withstand selection

 

X-type safety capacitors are classified into X1, X2 and X3 according to the withstand voltage, and the permissible peak impulse voltage overvoltage level in the safety level of safety capacitors: 2.5kV＜X1≤4.0kV, X2≤2.5kV, X3≤1.2kV.

Safety Classification of Safety Capacitors	Peak pulse voltage permitted in the application	Overvoltage rating (IEC664)
X1	>2.5kV、≤4.0kV	Ⅲ
X2	≤2.5lkV	Ⅱ
X3	≤1.2kV	Ⅰ

Y-type safety capacitor safety level: Y1≥250V, allow peak pulse voltage＞8KV; 150V≤Y2≤300V, allow peak pulse voltage＞5KV, Y4＜150V, allow peak pulse voltage＞2.5KV.

 

Safety Classification of Safety Capacitors	Insulation type	Rated voltage range	Peak pulse voltage permitted in the application
Y1	Double or reinforced insulation	≥250V	>8kV
Y2	Basic or Extra insulation	≥150V、≤250V	>5kV
Y3	Basic or Extra insulation	≥150V、≤250V	>Y3 high pressure resistant n/a
Y4	Basic or Extra insulation	<150V	>2.5kV

 

Different circuits to choose a different voltage resistance value of the safety capacitors, not too large or too small, for X capacitors, many times the choice of X2 capacitors.

 

2. The type of certification

 

Regardless of what components, as long as the formal certification, safety certification also includes product safety certification, environmental certification, energy certification, different countries have different safety regulations, some mandatory certification, there are many certifications, such as China's CQC certification, Germany's VDE certification, the United States of America's UL certification, the European Union's ENEC certification, the South Korean KC certification and so on. Selection of safety capacitors should be based on different occasions and different countries to choose different certified components.

 

3. The application of safety capacitors

 

Safety capacitors are widely used in small household appliances, power products, electromechanical motors, LED lighting, chargers, uninterruptible power supplies and so on.

 

1. Application of X safety capacitors

 

Inhibit electromagnetic interference

Anti-electromagnetic interference is the most common role of X capacitors, generally two pins across the zero line and the fire wire between the applicable high frequency, DC, AC, coupling, across the pulse circuit, can withstand the impact of over-voltage, generally used in parallel with the resistor, the purpose is to play a role in the discharge of charge.

 

 

 

①Capacitor Buck

 

Resistive buck is also often used in X capacitors, especially for low-cost finished products, the working principle of capacitive buck is to use the capacitance generated by the capacitor at a certain frequency of the AC signal to limit the maximum operating current. At the same time in the capacitor connected in series with a resistive element, the voltage obtained at the ends of the resistive element and the power consumption it generates depends entirely on the characteristics of this resistive element. Thus, capacitive voltage reduction is in fact current limitation by means of capacitive reactance, while the capacitor actually plays the role of a current limiter and dynamically distributes the voltage between the capacitor and the load.

 

 

②Filtering

 

X2 safety capacitors can be used as DC filtering use, can be used in parallel.

 

(2)Application of Y capacitor

 

Many isolated switching power supply in the primary and secondary Y capacitor is added to the secondary common mode current to provide a loop to the primary, reduce the common mode current on the output of the impact of the Y capacitor in series between the high-voltage ground and the low-voltage ground, sometimes two Y capacitors are used in series in order to improve the withstand voltage between the high-voltage ground and the low-voltage ground, and sometimes there is a lack of withstand voltage, resulting in the withstand voltage can not be hit by the capacitor, you can choose high-voltage ceramic capacitor as the Y capacitor usually connected to four cases. You can choose high-voltage ceramic capacitors as Y capacitors, Y capacitors are usually connected in four cases:

 

① Input, and common mode inductor to form a filter, L and N were added to the PE;

(ii) The positive and negative ends of the large energy storage capacitor are added to PE;

(iii) The output side is added to PE;

 

② Transformer primary and secondary jumper.

UF Capacitors offer featured safety capacitors include Y1 safety capacitors(400VAC),Y1 safety capacitors(500VAC),Y2 safety capacitors(250VAC).

 

 

 

 

UF Capacitors Y1Y2 Safety Capacitors Feature

 

• Wide capacitance range from 100pF to 4700pF
• Operating Temperature: -40℃～125℃
• Storage Temperature: 15℃~35℃
• Fix capacitors Y1 for electromagetic interference suppression and connection to the supply mains

has high dielectric coefficient ceramic dielectric and flame retardant epoxy resin package

 

Safety Approval Logo Markings

 

All safety-certified capacitors should have the proper logo markings on their casing.UF Capacitors Y1Y2

Country	Certification Body	Report Reference	Capacitance Range	Rated Voltage
USA Canada	UL CUL	UL60384-14	100～4700pF	X1Y1: 500VAC 1500VDC
China	CQC	GB/T6346.14-2015 IEC60384-14:201 3+AMD1:2016	100 ～4700pF
Germany	VDE	En 60384-14: 2017-04	100～4700pF
EU	ENEC	En 60384-14: 2017-04	100～4700pF

Safety capacitors also follow this principle.The picture below represents different Standard and certification body signs.

 

 

UF Capacitors Safety Disc ceramic cap Y1Y2 to replace Epcos/ TDK,Murata, Vishay etc always with shorter lead time and cost down 20%-40%.Check the following sheet find the perfect replacement to other brands.

 

 

Photo	Descriptiom	UFCapacitors' Series Code	Vishay	TDK/Epcos	Murata	AVX/Mallory	Kemet/Arcotronics
	X1Y1 Safety Ceramic Capacitor 400VAC/500VAC	Y1 Series	30LVS Series VY1 Series	CD45 Series	DE1 Series	K1Y Series	C900 Series KJN Series
	X1Y2 Safety Ceramic Capacitor 250VAC	Y2 Series	WYO Series 25Y Series VY2 Series VKO Series	CS45 Series	DE2 Series	KJY Series K2Y Series	C900 Series
	X2 Metallized Polypropylene Film Capacitor	X2 Series	MKP3382 Series MKP3384 Series MKP3392 Series	B32921C/D-B32928C/D Series B81 130 Series			R46 Series PHE840M Series PHE850 Series PMR-209 Series

 

 

 

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