# Georgia IAEI Toolbox

## Electrical Formulas

Motor Formulas
Tranformer Formulas

E = Voltage / I = Amps /W = Watts / PF = Power Factor / Eff = Efficiency / HP = Horsepower

 AC/DC Formulas To Find Direct Current AC / 1phase 115v or 120v AC / 1phase208,230, or 240v AC 3 phaseAll Voltages Amps whenHorsepower is Known HP x 746E x Eff HP x 746E x Eff X PF HP x 746E x Eff x PF HP x 7461.73 x E x Eff x PF Amps whenKilowatts is known kW x 1000E kW x 1000E x PF kW x 1000E x PF kW x 10001.73 x E x PF Amps whenkVA is known kVA x 1000E kVA x 1000E kVA x 10001.73 x E Kilowatts I x E1000 I x E x PF1000 I x E x PF1000 I x E x 1.73 PF1000 Kilovolt-Amps I x E1000 I x E1000 I x E x 1.731000 Horsepower(output) I x E x Eff746 I x E x Eff x PF746 I x E x Eff x PF746 I x E x Eff x 1.73 x PF746
 Three Phase Values For 208 volts x 1.732, use 360For 230 volts x 1.732, use 398For 240 volts x 1.732, use 416For 440 volts x 1.732, use 762For 460 volts x 1.732, use 797For 480 Volts x 1.732, use 831

E = Voltage / I = Amps /W = Watts / PF = Power Factor / Eff = Efficiency / HP = Horsepower

 AC Efficiency and Power Factor Formulas To Find Single Phase Three Phase Efficiency 746 x HPE x I x PF 746 x HPE x I x PF x 1.732 Power Factor Input WattsV x A Input WattsE x I x 1.732
 Power - DC Circuits Watts = E xI Amps = W / E
 Ohm's Law / Power Formulas P = watts I = amps R = ohms E = Volts

Voltage Drop Formulas
Single Phase
(2 or 3 wire)
VD = 2 x K x I x L
CM
K = ohms per mil foot

(Copper = 12.9 at 75°)

(Alum = 21.2 at 75°)
 Note: K value changes with temperature. See Code chapter 9, Table 8

L = Length of conductor in feet

I  = Current in conductor (amperes)

CM
= Circular mil area of conductor

CM= 2K x L x I
VD
Three Phase VD= 1.73 x K x I x L
CM
CM= 1.73 x K x L x I
VD