Procedure

• At the traversing section in the duct plane the Pitot static tube with the nose at center, facing the air in the air stream
• To the Pitot tube connect the Askania to measure velocity pressure, and inclined tube manometer to measure the static pressure. Level these two instruments and take their initial reading.
• Make wattmeter connections and start the fan. Use the symmetrical conical throttle provided at the duct outlet to vary the quantity in the duct.
• For each throttle bottle measure the
  • Motor input power
  • Fan RPM
  • Static and velocity pressures at the traverse section
• Measure the L and D values; obtain wet and dry bulb temperatures and barometric pressures at the fan inlet. Obtain a representative of dry bulb temperature inside the duct.