Typical Capacitance values for Control Cable?
Typical Capacitance values for Control Cable?
(OP)
I have a few ABB relays that are controlled by long distance cables. I want to determine the maximum cable length, so I am using the "Permissible single length for the control circuit conductors on contactor opening" table on sheet two of the following ABB published document:
http ://www.abb -control.c om/pdf/cat alog/ac100 0/1.77.pdf
However the table doesn't base max cable runs on the cable gauge/diameter but on the cable's line capacitance per uF/km. (Table showns mF/km, it is a typo.) I have no clue what the typical capacitance value is for 2c-#14, 2c-#12 or 2c-#12. I am using an Aluminum interlocked armored cable (TECK 90, 600V).
I understand that capacitance for cables depend on many factors: such as cable type, cable materials, capacitance between other phase lines, capacitance between ground, capacitance with other cables in proximity, etc... However, I am looking for "nominal" cables capacitance values that I can use as typical. Or a method / guideline that approximates cable capacitance. It is impossible to be precise, but a ballpark figure so I have something to work with in establishing estimated cable lenghts.
Thanks,
Majesus
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However the table doesn't base max cable runs on the cable gauge/diameter but on the cable's line capacitance per uF/km. (Table showns mF/km, it is a typo.) I have no clue what the typical capacitance value is for 2c-#14, 2c-#12 or 2c-#12. I am using an Aluminum interlocked armored cable (TECK 90, 600V).
I understand that capacitance for cables depend on many factors: such as cable type, cable materials, capacitance between other phase lines, capacitance between ground, capacitance with other cables in proximity, etc... However, I am looking for "nominal" cables capacitance values that I can use as typical. Or a method / guideline that approximates cable capacitance. It is impossible to be precise, but a ballpark figure so I have something to work with in establishing estimated cable lenghts.
Thanks,
Majesus





RE: Typical Capacitance values for Control Cable?
If you want to be safe, measure the cable yourself or use data developed from measurements on that particular run of cable.
Bill
--------------------
"Why not the best?"
Jimmy Carter
RE: Typical Capacitance values for Control Cable?
I may use the capacitance charts from Belden. It's for fire control/alarm cable... but it is the best I can find.
http://www.belden.com/pdfs/TechInfo/techinfo.htm
RE: Typical Capacitance values for Control Cable?
http://eca
RE: Typical Capacitance values for Control Cable?
However, I got these ABB relays and they referred to me to their publication for those relays. However the publish values in uF/km cable and not by cable diameter. Understandable as theoretical point of view, but realistically, how is one to know the capacitance of the control cable (2c-#12 teck) if it is in the design phase? (I can't implement Waross's suggestion.)
RE: Typical Capacitance values for Control Cable?
The following article may be useful. On my opinion use of DC operated contactors. It is better. See:
http://