Fan BHP
Fan BHP
(OP)
Gentlemen:
Reference: thread403-82316: Fan Horsepower equation derivation
I seem to lose out on this subject. Please note the following:
Fan BHP = (cfm x static press "w.c.) / (6356 x fan efficiency)
Fam Motor HP = fan bhp / motor efficiency
Following are values from a propeller fan manufacturer's catalog for a particular fan:
Static press. = 0.125"w.c. , cfm = 11,207 Fan motor HP = 1.437
By using the above formula fan BHP = (11,207 x 0.125) / (6356 x .7) = 0.31
Motor HP = 0.3148 / 0.9 = 0.35
There is enormous discrepancy between calculated Fan Motor HP of 0.35 and the fan OEM catalog value of 1.437 HP. This is typical of all fan OEM catalogs I see.
Can somebody shed some light?
Thank you and have a great day!
dunkin
Reference: thread403-82316: Fan Horsepower equation derivation
I seem to lose out on this subject. Please note the following:
Fan BHP = (cfm x static press "w.c.) / (6356 x fan efficiency)
Fam Motor HP = fan bhp / motor efficiency
Following are values from a propeller fan manufacturer's catalog for a particular fan:
Static press. = 0.125"w.c. , cfm = 11,207 Fan motor HP = 1.437
By using the above formula fan BHP = (11,207 x 0.125) / (6356 x .7) = 0.31
Motor HP = 0.3148 / 0.9 = 0.35
There is enormous discrepancy between calculated Fan Motor HP of 0.35 and the fan OEM catalog value of 1.437 HP. This is typical of all fan OEM catalogs I see.
Can somebody shed some light?
Thank you and have a great day!
dunkin





RE: Fan BHP
RE: Fan BHP
have a good day!
dunkin
RE: Fan BHP
A perfect installation with space up, and downstream of the fan would require only .35hp to move 11,000 cfm, under actual installation it requires 1.437 brake horsepower.
Is the actual motor 1.5hp or 2hp? Quark's comment has more to do with the size of the installed motor, not the published brake horsepower.
RE: Fan BHP
thanks for the response. The 1.437 BHP is off of actual fan performance curves. It corresponds to 11,200 cfm at 0.125"wc static pressure. The design engineer then has to allow for motor efficiency and pick a suitable motor that will have at least 1.437/0.8 = 1.79 HP power. The 1.437 BHP is a laboratory reading, which allows for smooth air flow upstream and downstream of fan. The above figures are from www.airturbine.com.
thanks again
dunkin
RE: Fan BHP
RE: Fan BHP
thanks for the input!
have a great day!
dunkin
RE: Fan BHP
Please do educate us on your findings (including your actual observation of power consumption).
Regards,