Electrical
Ohm's Law:

R = Ohms
E = Volts
I = Ampere
W = Watts

Ohms = Volts / Amperes (R = (E / I)) 

Amperes = Volts / Ohms (I = (E / R))

Volts = Amperes x Ohms (E = IR)

Watts = Volts x Amperes (W = EI)

AC CIRCUITS POWER CALCULATIONS

EF = Efficiency

PF = Power Factor

KW = Kilowatts

HP = Horsepower

Ph = Phases1000

Watts = 1 KW
Efficiency =
746 x Output HP
 Input Watts
 3Ph KW =
Volts x Amps x PF x 1.732
1000
3Ph Amps =
      746 x HP     
1.732 x Eff. x PF
 3Ph EF =
           746 x HP              
 1.732 x Volts x Amps x PF
3Ph PF =
        Input Watts        
Volts x Amps x 1.732
 1Ph-KW =
Volts x Amps x PF
1000
1Ph Amps =
      746 x HP     
Volts x Eff. x PF
 1Ph EF =
        746 x HP       
Volts x Amps x PF
1Ph PF =
  Input Watts  
Volts x Amps
 3 PhHP =
Volts x Amps x 1.732 x Eff. x PF
746
1Ph HP =
Volts x Amps x Eff. x PF
746