Kansas City Board of Public Utilities BPU Serving the Water and Electric Needs of Kansas City, Kansas
       
 
Electrical Formulas

DIRECT CURRENT
 
                                AMPS = WATTS/VOLTS
                                          I = P/E

                                WATTS = VOLTS x AMPS
                                           E = P/I
 
                                VOLTS = WATTS/AMPS     
                                          E = P/I
 
                                HORSEPOWER = (V x A x EFF)/746
 
                                EFFICIENCY = (746 x HP)/(V x A)
 
SINGLE PHASE – ALTERNATING CURRENT
 
                                AMPS = WATTS/(VOLTS x PF)
                                          I = P/(E x PF)
                                         A = W/(V x PF)
 
                                WATTS = VOLTS x AMPS x PF
                                           P = E x I x PF
                                          W = V x A x PF
 
                                VOLTS = WATTS/AMPS
                                          E = P/I
                                          V = W/A
 
                                VOLTAMPS = VOLTS x AMPS
                                                  E = P/I
                                                  V = W/A
 
                                HORSEPOWER = (V x A x EFF x PF)/746
 
                                POWER FACTOR = INPUT WATTS/(V x A)
 
                                EFFICIENCY = (746 x HP)/(V x A x PF)
 
THREE PHASE ALTERNATING CURRENT
 
                               AMPS = WATTS/(1.732 x VOLTS x PF)
                                         I = P/(1.732 x E x PF)
 
                                WATTS = 1.732 x VOLTS x AMPS x PF
                                           P = 1.732 x E x I x PF
 
                                VOLTS = WATTS/AMPS
                                          E = P/I
 
                                VOLT-AMPS = 1.732 x VOLTS x AMPS
                                                  VA = 1.732 x E x I
 
                                HORSEPOWER = (1.732 x V x A x EFF x PF)/746
 
                                POWER FACTOR = INPUT WATTS/(1.732 x V x A)
 
                                EFFICIENCY = (746 x HP)/(1.732 x V x A x PF)
 
FULL LOAD FORMULA
 
                                FULL LOAD AMPS = KVA/VOLTS 
Ohm's Law

Ohm's Law defines the relationships between (P) power, (E) voltage, (I) current, and (R) resistance. One ohm is the resistance value through which one volt will maintain a current of one ampere.

( I ) Current is what flows on a wire or conductor like water flowing down a river. Current flows from negative to positive on the surface of a conductor. Current is measured in (A) amperes or amps.

( E ) Voltage is the difference in electrical potential between two points in a circuit. It's the push or pressure behind current flow through a circuit, and is measured in (V) volts.

( R ) Resistance determines how much current will flow through a component.

( P ) Power is the amount of current times the voltage level at a given point measured in wattage or watts.
Ohm's law basically states that the amount of current in a circuit varies directly with the voltage and varies inversely with the resistance.
Ohm’s Law Symbols:
E =VOLTS or (V = VOLTS)
P =WATTS or (W = WATTS)
R = OHMS or (R = RESISTANCE)
I =AMPERES or (A = AMPERES)
HP = HORSEPOWER
PF = POWER FACTOR
kW = KILOWATTS
kWh = KILOWATT HOUR
VA = VOLTAMPERES
kVA = KILOVOLT-AMPERES
C = CAPACITANCE
EFF = EFFICIENCY (expressed as a decimal)
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