Re: Fans vs. Horsepower

Jim Lill (jpl@vectorbd.vivanet.com)
Tue, 29 Apr 1997 17:07:37 +0000 (UTC)

To all that have questioned my horsepower calculation for Fans....

Please note that I said WORST case. Obviously the fans don't draw 25A
through their 25A fuses. Lacking any actual measurements I made those
worst case assumptions. So, if it helps, here's some guesses that might be
closer:

Fans @ 12A each = 24 amps total
14V X 24A = 336 Watts
w/85% alt. eff., mech work = 395 mech. watts OR 0.53 mechanical horsepower

The purpose of my first message was to show even on a bad day it was less
than 2HP which I think is less than any engine/belt driven fan. Anybody
got a number on that?

As far as the 100A from the alternator someone noted, those 1400 were
mechanical watts input not output watts from the unit.