The electric machinery of 22 kilowatt needs the issue of the copper cash of how many square, live in miscellaneous altar to had shared similar problem with everybody before, here makes detailed introduction to everybody again; Know the bear that use phone will choose cable, basically have the following move: It is give computational electric current according to be begged with electric bear, 2 it is according to computation electric current opens choice cable, 3 it is basis pressing falls the demand will check the cable of the choice; The home resides miscellaneous altar to choose move one by one to be analysed to everybody with respect to the basis below.
- According to computation electric current chooses the alternative that we want to make clear cable above all, do not choose according to the electric current that start, the starting kind that does not need to consider electric machinery is when choosing cable so, the starting means as to electric machinery is another problem then, still do not do here discuss; Foregone now condition is: The bear that use phone is the electric machinery of 22 kilowatt, so the three-phase report that voltage is 380V for certain; φ of power factor Cos we are chosen by what illuminate convention, cos φ takes a cost for 0.8, sealed is I of computational electric current; So we the 3UIcos of √ of ＝ of computational formula P according to power φ , so computational electric current is φ of 3Ucos of √ of I ＝ P/ , among them foregone is power P it is 22kw, voltage U is 380V, cos φ is power factor, what we take is 0.8; So 22000W/ of ＝ of φ of 3Ucos of √ of P/ of ＝ of I of computational electric current (380 × of 1.732 × 0.8) ≈ 42A; According to computation formulary computation comes out this, we check again according to experience electric current, electrical engineering and commonly used experience law is such: In three-phase report, the power load of every 1kw needs the electricity of 2A, now is 22kw, so that is to say the electricity that the electric machinery of 22kw needs is 22kw × 2 ＝ 44A; The electric current of numerate of two kinds of method plan has above a little a bit error, so safe we choose for the purpose of big electric current, choose 44A namely.
- We had begged the computational electric current that gave electric machinery above, I ＝ 44A, so we can choose cable according to this computation electric current, the simplest way investigates cable safety namely current-carrying capacity watch will choose cable; The watch can know the safe current-carrying capacity that we examine cable, the cupreous core cable of 10 square is different insulation form is different lay the current-carrying capacity limits below the condition is 48A arrive between 80A, the cupreous core cable that so we can choose 10 square is most reasonable, if conservative word can choose the cupreous core cable of 16 square; After choosing good cable, we check again according to experience: The copper cash that the experience data that we know is every square allows current-carrying capacity roughly limits is 5A to 8A, so the current-carrying capacity of 10 square copper cash is 50A arrives between 80A, so we can see the cupreous core electrical wiring that chooses 10 square is most reasonable.
- We know the fluctuant limits of voltage does not exceed 5% , so namely 5% ＝ of 380V × 19V, namely voltage wave motion does not exceed 19V; Next we again according to ＝ of formulary △ U (P × L) / (A × S) , among them △ U is 19V, power P is 22KW, a is conductor material qualitative coefficient, copper is 77, the cut area that S is lead namely 10 square millimeter; So 77 × of × of 19V of ＝ of S/P of × of A of × of U of L ＝ △ 10/22 ＝ 665 meters, the cupreous core wire that 10 square use in the distance in 665 meters that is to say is pressed falling is to be able to satisfy a requirement.
Need the issue of the copper cash of how many square about the electric machinery of 22 kilowatt, live in miscellaneous altar to be analysed to everybody, the hope can help great master! Above is individual viewpoint is discussed for everybody communication only use, if insufficient place welcomes everybody to leave a message,discuss point out mistakes so that they can be corrected! Still adjure everybody to pay close attention to household miscellaneous altar finally, reside miscellaneous altar to nod assist to comment on transmit to the home more, thank extremely!
