Power – AC Circuits, Power – DC Circuits, Mechanical, Fans & Blowers, Pump Motors
OHMS LAW
Volts (E) = Amps (I) x Ohms (R)
Amps (I) = Volts (E) / Ohms (R)
Ohms (R) = Volts (E) / Amps (I)R=Ohms, E=Volts, I=Amperes
POWER – AC CIRCUITS
Abbreviations:
Eff. = Efficiency
PF = Power Factor
KW = Kilowatts
HP = Horsepower
Efficiency = 746 x Output HP
Input Watts
3ÿ KW = Volts x Amps x PF x 1.732
1000
3ÿ Amps = 746 x HP
1.732 x Volts x Eff. x PF
3ÿ Eff. = 746 x HP
1.732 x Volts x Amps x PF
3ÿ PF = Input Watts
Volts x Amps x 1.732
1ÿ KW = Volts x Amps x PF
1000
1ÿ Amps = 746 x HP
Volts x Eff. x PF
1ÿ Eff. = 746 x HP
Volts x Amps x PF
1ÿ PF = Input Watts
Volts x Amps
HP (3ÿ) = Volts x Amps x 1.732 x Eff. x PF
746
HP (1ÿ) = Volts x Amps x Eff. x PF
746
1 KW = 1000 Watts
POWER – DC CIRCUITS
Watts = Volts x Amps
Amps = Watts
Volts
HP = Volts x Amps x Eff.
746
MECHANICAL
Torque = HP x 5250
RPM
(Result is lb.ft. Multiply by 12 for lb.in.)
Torque = HP x 63025
RPM
(Result is in lb.in. Divide by 12 for lb.ft.)
HP = Torque (lb.ft) x RPM
5250
HP = Torque (lb.in.) x RPM
63025
1 HP = 3 lb. ft. @ 1750 RPM
1 HP = 36 lb.in. @ 1750 RPM
FAN AND BLOWER MOTORS
Abbreviations:
CFM = Cubic Feet per Minute
Pressure lb.in./ sq.ft.
HP = CFM x Pressure
33000 x Eff.
PUMP MOTORS
Abbreviations:
GPM – Gallons per Minute
S.G. – Specific Gravity
Eff. = Pump Efficiency
HP = GPM x Head in Feet x S.G.
3960 x Eff.
Head in Feet = 2.31 P.S.I.G.
