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# Formulas and Calculators

 Calculators
Source: Handymath.com

 Application Formulas

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

T = Shaft Torque (lb-in.)
D = PD of Sprocket, Pinion or Pulley (in.)

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

 Formulas for Electricity

(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 + ....Resistancen

(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/Resistancen

(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