Tuner wrote: ↑Sat May 08, 2021 2:33 pm
lc-gtr-1969 wrote: ↑Sat May 08, 2021 1:44 am
Tuner wrote: ↑Fri May 07, 2021 7:59 pm
That belt is 1/2 or 5/8 inch wide. How much power goes to propelling the mower vs. turning the blades?
Come on people, look at the 5 HP electric motor on your shop air compressor, do you see two 5/8" belts? A 3/8" V belt is not going to deliver anywhere close to 30 HP and last 50,000 miles.
If you do not believe the data, an if you have access to a dyno- why don't you spend 30 minutes to run up a car and remove the mech. fan and post before and after data? I am sure plenty would be interested.
See, this is what happens when you don't read the whole thread and just jump right in with a kneejerk reaction instead of applying you maff skilzz. 1 HP = 746 Watts. 30 HP = 22371 Watts / 12 V = 1,864.25 Amps. A large electric fan assembly listed in Summit which has two fans/motors is rated at 50 amps. 50A x 12V = 600 Watts 1 HP = 746 Watts. It is ridiculous to think a fan driven by a single 3/8" belt is absorbing 30 HP.
Tuner wrote: ↑Thu May 06, 2021 5:58 pm
blackford wrote: ↑Thu May 06, 2021 12:49 pm
I'm sorry, but am I the only one who thinks that 30 HP to turn a fan is absurd? So, I would need to take a very powerful 30 HP electric motor that spins the fan up to speed (either directly or by gearing it up) to move the same amount of air as the same fan being spun by an engine? Does that seem reasonable to anyone?
Not reasonable at all, 30 HP is just nuts, yellow journalism. 30 HP = 22371 Watts / 12 V = 1,864.25 Amps. Who wants to try again?
Once upon a time on a chassis dyno on a hot summer day with a 355 SBC short-track car that had no fan at all it started getting warmer than ideal with just a 110V squirrel cage fan blowing at it so we put one of those molded black plastic fans on it about 12"-14" diameter and it did not change the RWHP at all but it did cool the engine just fine so we left it on and made a shroud out of one of the shop's Rubbermaid trash cans that serendipitously was the perfect size, length and diameter, when cut short and attached with tranny cooler zip ties through the heater core and the lip of the trash can.
You too, can become a belt application engineer with Design IQ and DF-Pro.
Now when Horton renews my subscription, I'll post up a graph of fan performance.
https://www.gates.com/us/en/knowledge-c ... tware.html
Relating the power back to 12V amps may not be the proper approach. But, if you raise the volts to 415 or so, then the current becomes manageable, or believable. I can assure you that a fan takes more than a few HP to create a deltaP and the subsequent volume flow. This could be why Teslas use a 600v motor to transmit "Ludicrous" torque?
Using Power = torque x omega (rad/sec), it is easy to see how fan hp (kW) numbers are "fathomable."
Also, trying to determine fan power backwards from aero and drag forces using some relative velocity is best left to the CFD types. I'm not sure how one could grab a velocity, bulk or otherwise, and demonstrate fan power is proportional to v^3. Now that I've stated it, though, someone will come up with a version of an explanation.
Rob is still looking for his fan solution to have an edge on his LS street competition and we haven't been able to convince him that a thermostatic clutch fan is the smart way to go. At the very least the discussion is entertaining.