- CFM of compressed air required to raise a known system pressure
to a desired system pressure:C2 = Required CFM total
C1 = Existing or known CFM
P2 = Desired pressure
P1 = Known PressureEXAMPLE: A 75 HP Compressor rated at 320 CFM t 125 PSIG will hold only 85 PSI and we desire 125 PSI.
C1 = 320 CFM
P2 = 125 + 14.7 (139.7)
P1 = 85 + 14.7 (99.7)
C2 = 448.39 Total CFM required
We need an additional 128.39 CFM to raise system pressure to the desired level.
- Simple Energy Formula:Motor Efficiency = Cost per KW X .746 (Power Factor) X Hours of operation X Brake horse power*Note: No electric motor is 100% efficient, most will average 92-95% efficient.
- PSI VS. BHP (Rule of thumb):For every 1 PSIG pressure drop, BHP (Brake horsepower) goes down ½ %.