Useful Formulas

 

Formulas For Electrical Motors:

To Find: Direct
Current
Single Phase Three Phase
Horse Power E x I x EFF
746
E x I x EFF x PE
746
1.732 x E  x I x EFF x PF
746
Current 746 x HP
E x EFF
746 x HP
E x EFF x PF
746 x HP
1.732 x E x EFF x PF
Efficiency 746 x HP
E x I
746 x HP
E x I x PF
746 x HP
1.732 x E x I x PF
Power Factor --------- Input Watts
E x I
Input Watts
1.732 x E x I
                            E     =  Volts                        HP = Horsepower            PF = Power Factor (decimal)
                                     EFF = Efficiency (decimal)    I    = Amperes
Formulas For Electrical Circuits:
To Find: Direct  Current Single Phase Three Phase
Amperes Watts
Volts
Watts
Volts x Power Factor
Watts
1.732 x Volts x Power Factor
  -------------------- Volts x Amperes Amperes 1.732 x Volts x Amperes
Watts Volts x Amperes Volts x Amperes
x Power Factor
1.732 x Volts x Amperes
x Power Factor
OHMS Law Capacitance in Microfarads at 60 HZ.
Ohms = Volts/Amps (R=E/I)
Amps = Volts/Ohms (I=E/R)
Volts  = Amps x Ohms (E=IR)
Capacitance = 2650 x Amperes
                                Volts

Capacitance = 2.65 x kVAR
                          (Volts) squared