Criteria for select coupling capacitors

[carlosm]

I have to points of high voltage with PLC communication, but the supplier give me to different couples capacitors, thats ok? or both must be the same value?

 

[nbucska]

The impedance of a C is Zc = -j /(2*pi*Freq *C) [Ohm]=
[1/(Hz*F)] and j=square_root(-1).

If you know the input circuit, you shouldn't have difficulty
calculating the effect of using different value.


<nbucska@pcperipherals.com>

 

[electricpete]

I remember reading in Westinghouse' Applied Protective Relaying the basis for capacitance selection. I don't remember details but I think it involved a calculation including parameters from the associated potential transformer. I don't think that capacitors of different capacitance should be substitutes.

 

[jbartos]

Suggestion: The PLC interfaces should be carefully scrutinized and the PLC manufacturer could provide a tech support for the correct capacitor ratings.