Common Motor Formulas
Ohms Law:
Ohms=Volts/Amperes Amperes=Volts/Ohms Volts=Amperes x Ohms
Power - AC Circuits - 3 Phase:
Efficiency = 746 x Output Horspower
               Input Watts 		KW = Volts x Amps x Power Factor x 1.732
                1000		 Amps =    ________746 x Horsepower__________
               1.832 x Volts x Efficiency x Power Factor
Power Factor =____Input Watts____
                         Volts x Amps x 1.732 		  HP = Volts x Amps x 1.732 x Efficiency x Power Factor
             1.832 x Volts x Efficiency x Power Factor
Motor Application Equations:
Torque (lb ft) = Horsepower x 5250
                       RPM		   Horsepower = Torque (lb ft) x RPM
                         5250
Time for Motor to Reach Operating Speed:
Seconds = ___WK2 x Speed Change____
                 308 x Avg. Accelerating Torque 		  WK2 = Inertia of Rotor + Inertia of Load (lb-ft2)
Avg. Acc. Torque = ((FLT + BDT)/2)+BDT+LRT
                               3		 Load WK2(@ Motor Shaft)= WK2(load)xload RPM2
                                           Motor RPM2		 Shaft Stress (psi) =______HP x 321,000______
                                    RPM x Shaft Diameter3
For Pumps:
Horsepower = GPM x Head in Feet x Specific Gravity
                                3960 x Efficiency of Pump
For Fans and Blowers:
Horsepower = __CFM x Pressure (psf)__
                        33000 x Efficiency of Pump