Formulas and Calculators

• Calculator for Outside Diameter of Roll of Material
• Calculator for Rolled Length of Roll of Material
  
• Electricity Cost Calculator
• Calculation of Liquid Volume in a Horizontal Cylindrical Container
• Calculation of Volume of the Shell of a Tube or Pipe
  

  1HP = 36 lb-in. @ 1750 rpm
  1HP = 3 lb-ft @ 1750 rpm

               Torque (lb-in.) x rpm  
  HP =             63,025

                Force (lb) x Velocity (ft/min.)
  HP=                33,000

  Velocity (ft./min.) = 0.262 x Dia. (in.) x rpm
  Torque (lb-in.) = Force (lb) x Radius (in.)

                           hp x 63,025
  Torque (lb-in.) =        rpm

  Mechanical           Output hp 
  Efficiency    =       Input hp         x 100%

                          OT (lb-in.) x Output rpm
  Output hp    =              63,025

  OT = Input Torque x Ratio x Efficiency
            OT= Output Torque

                       Input rpm  
  Output rpm =    Ratio

              2 TK 
  OHL =     D

  OHL = Overhung Load (lb)
       T = Shaft Torque (lb-in.)
       D = PD of Sprocket, Pinion or Pulley (in.)
       K = Overhung Load Factor

  Overhung Load Factors:
        Sprocket or Timing Belt............ 1.00
        Pinion & Gear Drive................... 1.25
        Pulley & V-Belt Drive................. 1.50
        Pulley & Flat Belt Drive.............. 2.50
        Variable Pitch Pulley................. 3.50

  kW = hp x 0.7457
  in.= mm/25.4
  Temp. ºC = (ºF - 32) x 0.556
  Temp. ºF = (ºC x 1.8) + 32
  Torque (lb-in.) = 86.6 x kg·m
  Torque (lb-in.) = 8.85 x N·m
  Torque (lb-in.) = 88.5 x daN·m

(1) Ohms Law (DC Current):
                                    Voltage in volts         =    Power in watts
  Current in amps =     Resistance in ohms            Voltage in volts

 

  Voltage in volts = Current in amps x Resistance in ohms

  Voltage in volts = Power in watts / Current in amps

 

  Power in watts = (Current in watts)² / Resistance in ohms

  Power in watts = Voltage in watts x Current in amps

  Power in watts = (Voltage in   volts)² / Resistance in ohms

  Resistance in ohms = Voltage in volts / Current in amps

  Resistance in ohms = Power in watts / (Current in amps)²

(2) Resistors in Series (value in Ohms):

  Total Resistance = Resistance₁ + Resistnace₂ + ....Resistance_n

(3)  Resistors in Parallel   (values in Ohms):
                                  Resistance₁ x Resistance₂  
   Total Resistance =       Resistance₁ + Resistance₂

(4) Multiple Resistors in Parallel (value in Ohms):

  Total Resistance =                           1                                          
                            1/Resistance₁ + 1/Resistance₂ + ....1/Resistance_n

(5) Ohms Law (AC Current)

In the following AC Ohms Law formulas, q is the phase angle in degrees by which current lags voltage ( in an inductive circuit) or by which current leads voltage ( in a capacitive circuit).  In a resonant circuit (such as normal household 120VAC) the phase angle is q² and Impedance = Resistance. and Impedance = Resistance. and Impedance = Resistance.

                               Voltage in volts  
  Current in amps =   Impedance in ohms

 

                                                 Power in watts       
  Current in amps =    Voltage in volts x cos q

  Voltage in volts = Current in amps x Impedance in ohms

                                       Power in watts            
  Voltage in volts =     Current in amps x cos q

  Impedance in ohms = Voltage in volts / Current in amps
  Impedance in ohms = Power in watts / (Current amps² x cos q)
  Impedance in ohms = (Voltage in volts² x cos q) / Power in watts
  Power in watts = Current in amps² x Impedance in ohms x cos q


  Power in watts = Current in amps² x Voltage in volts x cos q

                               (Voltage in volts)² x cos q
  Power in watts =        Impedance in ohms