If you are interested in calculating the HP of a motor, multiply the torque (expressed in lb-ft) by the engine speed (in RPM) and divide by a conversion factor of 5252. So for this motor:

300 lb-ft x 500 RPM/5252 = 28.6 HP

I don't know why you have included "wind force 100 lbs."

In SI unit 1 N·m = 0.738 ft·lb
so 1/0.738 = 1 ft·lb
1.355 N·m = 1 ft·lb
(1.355 x 100 x 300) N·m = (100 x 300)ft·lb
406.5 N·m = 300 ft·lb
so P = nT/9.55
where P in watt, 'n' is an rpm, T in Nm and 9.55 is a consttant
P = (500x406.5)/9.55
P = 21282.7Watt or P = 21282.7/746 P = 28.5 hp because 1 hp = 746 watt
please informed me on my e-mail if it is according to your requirement ([email protected])

In SI unit 1 Nm = 0.738 ftlb
so 1/0.738 = 1 ftlb
1.355 Nm = 1 ftlb
(1.355 x 100 x 300) Nm = (100 x 300)ftlb
406.5 Nm = 300 ftlb
so P = nT/9.55
where P in watt, 'n' is an rpm, T in Nm and 9.55 is a consttant
P = (500x406.5)/9.55
P = 21282.7Watt or P = 21282.7/746 P = 28.5 hp because 1 hp = 746 watt
please informed me on my e-mail if it is according to your requirement ([email protected])