Electrical formula sheet, Cheat Sheet of Physics

Download Electrical formula sheet and more Cheat Sheet Physics in PDF only on Docsity! Electrical Formulas General Formulas The following formula wheel can be used for all direct current circuits and alternating current circuits with unity power factor. Voltage Drop Formulas Voltage Drop (10)=2xLxKxI CM Voltage Drop (30) = 1.732 xLxKxI CM K = direct current resistance for a 1,000 circular mil conductor 1,000 feet long operating at 75°C.. K= 12.9 ohms for copper K= 21.2 ohms for aluminum (From NEC - Chapter 9, Table 8) L= One way length of circuit in feet 1 = Current in conductor in amperes Voltage Drop (10)=RxI R = Resistance of both conductors Voltage Drop (38) = R x Ix 1.732 R = Resistance of one conductor DELTA Vi = V Line = Source Voltage ‘Vp = V Phase = Phase Voltage ‘Vi = Vp 1_= I Line = Line Current Ip= I Phase = Phase Current L x 1.732 Ip=1,/1.732 Power = W = V3 x Vili cos @ =31/R =3V,lp cos 6 WYE ‘Vi = V Line = Source Voltage Vp = V Phase = Phase Voltage Vi = Vex 1.732 I, = I Line = Line Current Ip= I Phase = Phase Current IL=b Power = W = ¥3 x Vilicos 0 =31PR =3V,l, cos @ True Power Power Factor = —\oparent Power Note 1 - Use copper conductors for all problems, unless otherwise specified. Note 2 - One horse power is equal to 746 watts. Note 3 - Power factor (P.F.) = cos @ = R/Z, Z = Impedance. Note 4 - Efficiency = Output/Input