Restrain with 0 lines in live wire between shunt-wound capacitance, say commonly for X capacitance. Because position of this capacitance connective also compares a key, same need accords with relevant and safe level. X capacitance also attributes one of safe electric capacity likewise. According to real need, the look value that the look value of X capacitance allows to compare Y capacitance is great, but must be in right now the two end of X capacitance are shunt-wound a safe resistor, when be being used at preventing power supply cord to unplug to insert, as a result of this capacitance fill discharge process and send outlet of power supply cord long electrified.

 

Safe level sets, when be being unplugged in the machine power supply cord in the job, inside two seconds, outlet of power supply cord the voltage with two electrified end (or right potential) 30% what must be less than voltage of rated before job.

 

Between live wire and ground wire and the capacitance that receives between 0 lines and ground wire, common be called by a joint name is Y capacitance. Position of connective of capacitance of these two Y is more crucial, must need to accord with relevant and safe level, cause electronic equipment leakage of electricity in case or housing is electrified, endanger person safety and life easily. They attribute safe electric capacity, ask capacitance value cannot slant thereby big, and compression must taller. Usually, the job is in semi-tropical machine, the requirement cannot exceed 0.7mA; job to be in to electric current of floor drain report temperate zone machine, ask right residual current cannot exceed 0.35mA. Accordingly, the total capacity of Y capacitance cannot exceed 4700PF commonly (472) .

 

Special point out:

 

The X capacitance that serves as one of safe capacitance, also ask to must obtain safe check to measure the attestation of the orgnaization. X capacitance is general mark has safe attestation mark and compression AC250V or AC275V model of written characters, but its true dc compression is as high as 2000V above, when using, do not use at will nominal compression AC250V or of DC400V and so on common capacitance will substitute.

 

Regard the Y of safe capacitance as capacitance, the requirement must obtain safe check to measure the attestation of the orgnaization. Y capacitance exterior is orange or blue more, general mark has safe attestation to indicate (wait for a label like UL, CSA) with compression AC250V or AC275V model of written characters. However, its true dc compression is as high as 5000V above. Must emphasize, y capacitance is not used at will nominal compression AC250V or the common capacitance of DC400V and so on will substitute.

 

Normally, x capacitance is chosen more be able to bear or endure ripple electric current is bigger get together fat is filmy kind of capacitance. The capacitance of this kind of type, volume is larger, the electricity that Dan Jiyun makes the instant charge discharge is very big also, and its internal resistance is corresponding and lesser. The index of electric current of common capacitance ripple is very low, dynamic internal resistance is taller. Replace X electric capacity with common capacitance, cannot satisfy a standard besides capacitance compression besides, index of ripple electric current also accords with a requirement hard.

 

According to IEC 60384-14, capacitor cent is X capacitance and Y capacitance,

 

1.X capacitance is to point to cross the capacitor between L-N,

2.Y capacitance is to point to cross the capacitor between L-G/N-G.

(L=Line, n=Neutral, g=Ground)

 

Divide again below X capacitance for X1, x2, x3, main difference depends on:

 

1.X1 is able to bear or endure high pressure is more than 2.5 KV, be less than be equal to 4 KV,

2.X2 is able to bear or endure high pressure is less than be equal to 2.5 KV,

3.X3 is able to bear or endure high pressure is less than be equal to 1.2 KV

 

Divide again below Y capacitance for Y1, y2, y3, y4, main difference depends on: (Be able to bear or endure volts d.c. grade)

 

1.Y1 is able to bear or endure high pressure is more than 8 KV,

2.Y2 is able to bear or endure high pressure is more than 5 KV,

3.Y3 is able to bear or endure high-pressured N/a

4.Y4 is able to bear or endure high pressure is more than 2.5 KV

 

They are used in power source filter, have effect of wave of power source filter, be opposite respectively in all model, trouble of the labor that need a standard has filter wave effect.

 

Bringing compasses electric capacity is to point to use at such circumstance, namely after capacitor invalidation, won’t bring about electrical shock, do not endanger person security, it included X capacitance and Y electric capacity.

 

X capacitance is bond in power line two lines (L-N) the capacitance between, choose metallic film capacitance commonly; Y capacitance is to part bond in power line two lines are mixed between the ground (L-E, n-E) capacitance, it is to appear in couples commonly. Be based on the limitation of leakage current, y capacitance is worth cannot too big, general X capacitance is UF class, y capacitance is NF class. X capacitance restrains the interference that need a standard, y capacitance is restrained in all modular interference.

 

Install compasses capacitance to bring congruent level

 

The order and degree of overvoltage of voltage of peak value pulse that in installing the class application such as compasses capacitance safety, allows (IEC664)

Ⅲ of 2.5kV ≤4.0kV of X1 ＞

Ⅱ of X2 ≤2.5kV

X3 ≤1.2kV ——

 

Bring the class insulation kind such as compasses capacitance safety rated voltage limits

 

Y1 double insulation or strengthen insulation≥250V

Y2 basic insulation or additional insulation ≥150V ≤250V

Y3 basic insulation or additional insulation ≥150V ≤250V

Y4 basic insulation or 150V of additional insulation ＜

 

The capacitance of Y capacitance must be restricted, achieve control to be below rated frequency and rated voltage action thereby, the size of the leakage current that has shed it and the purpose that affect to systematic EMC function.

 

GJB151 stipulates the capacity of Y capacitance should not be more than 0.1uF. Y capacitance is divided outside according with compression of corresponding voltage of electrified wire netting, still ask this kind of capacitor is in electric have enough safe surplus with mechanical performance side, avoid to play phenomenon of occurrence puncture short circuit in extremely harsh ambient conditions, the compression function of Y capacitance has important sense to tutelar body safety.

 

Complement to chose the place that should notice again:

 

One. Restrain interference of power source electromagnetism to use capacitor

　　

The line should be crossed in power source when capacitor is being used to eliminate noise in circuit, have normal voltage only not just, still must consider unusual pulse voltage (like lightning) generation, this may bring about capacitor fume or on fire. So, the safe level of the capacitor that cross a line sets strictly to having in different country, reason must use the capacitor that passes safe attestation.

 

2. Do not allow to use dc container as the capacitor that cross a line uses:

　　

To X2 kind restrain interference of power source electromagnetism to should apply to the situation that won’t cause electrical shock hazard when capacitor invalidation with capacitor, if power source crosses circuit join, can bear the pulse voltage of 2.5kV.

  

To Y2 kind restrain interference of power source electromagnetism to should apply to the situation that won’t cause electrical shock hazard when capacitor invalidation with capacitor, use at power source crosses circuit to join, can bear the pulse voltage concussion of 5kV, do not send produce puncture phenomenon.          

                       

1.X capacitance, polystyrene (filmy ethylene) capacitance, the proof voltage of polystyrene is taller, suit the high-pressured pulse absorption of EMI circuit.

 

2. capacity calculates: General capacitance of two class X, before one class uses 0.47uF, the 2nd base with 0.1uF; Only course uses 0.47uF. Had not compared convenient computational method at present. (the power of the size of capacitance capacity and power source does not have immediate impact)

 

What X capacitance place says is peak value voltage, not be rated voltage, x capacitance uses MPX commonly (metallization polypropylene modular capacitance) their rated voltage also is hundreds of bend over, if designation of a kind of X2 is MPX-X2-250VAC/275VAC.