Nate Formulas questions and answers 2023 latest

Nate Formulas questions and answers 2023 latestFan law: Pulley size Formula DPm X RPMm = DPf X RPMf DP=Diameter of Pulley f=Fan or Driven m=Motor or Driver Actual Brake HP of a motor BHP = HPnp( Amps/FLA) np = Name plate Synchronizes speed of a motor 7200 / # of poles Convert Velocity pressure (Vp) into Feet Per Minute (FPM) FPM = 4005(sqrt of Vp) Convert V(velocity) into CFM CFM = Asqft X Vfpm Asqft = Area of the ductwork in square feet Vfpm = Velocity in Feet Per Minute Tp(total pressure) equals Tp = Static (Sp) + Velocity (Vp) The formula to figure the BTUH of an ac system using field measurements BTUH = 4.5(CFM) x (Delta Enthalpy) Fan law: Basic fan law formula BHP2 = BHP1 X ((RPM2 / RPM1)cubed) Shows that required power of a motor varies by the Cube of the speed increase of that motor. The formula to figure the CFM of a Gas furnace using field measurements. CFM = BTUH(output) / 1.08 X Delta T 1.08 = 60(.075 X 0.24) 60 = Adjust formula to one hour Density of Dry air (.075) Specific heat (0.24) of Dry Air The formula to figure the CFM of an electric furnace CFM = (E X I) X 3.414 / 1.08 X Delta T E X I = watts of the heating elements 3.414 converts watts to BTU's Fan law: The formula to determine BTUH of a Gas furnace using field measurements. BTUH = 1.08 X CFM X Delta T Chiller load formula BTUH = GPM X 60 X 8.33 X Delta T or BTUH = GPM X 500 X Delta T Convert Centigrade to Fahrenheit C = (F - 32) / 1.8 Convert Fahrenheit to Centigrade F = (1.8 X C) + 32 U value of insulation is equal to? 1/R Where R is the R value of the insulation. R value of insulation is equal to? 1/U Where U is the U value of the insulation. Area of a circle A = pi X Rsq Formula for Power in Watts W = I X E ohms law E = I X R Formula for finding the resistance of a Parallel circuit Rt = (R1 X R2) / (R1 + R2) or 1 / (((1/R1) + (1/R2) + (1/R3) + ....))) If all resisters are the same value divide the common value by the # of resisters Formula for finding the total caps in parallel Ct = C1 + C2 + C3 Formula for capacitors in series 1 / (1/C1 + 1/C2 + 1/C3) Find Watts when BTU's are known W = BTU's X .293 .293 is the reciprocal of 3.414, the number of BTU's in a watt. Compression Ratio (CR) CR = Head PSIA / Suction PSIA Formula for PSIA when Inches of HG is known PSIA = (30 - Inches HG) / 2 Figure the expected temperature drop across a chiller Delta T = BTUH / (GPM X 500) Circumference of a circle C = pi X D Fan law: The relationship of CFM to RPM change CFM1/CFM2 = RPM1/RPM2 Doubling RPM doulbles CFM Figure Approximate BHP when motor amps and applied voltage is known Approx BHP = (E X I)/746 To many factors to make this a good formula Formula to clock a furnace or boiler BTUH = [(cuft X 3600)/sec.] x cf x 1000 cuft = amount of gas measured at meter; 3600 = secs in an hour; sec = time taken to measure gas used in secs. ; cf = correction factor (usually around 3.04)