Oregon_Rob
ArboristSite Guru
How many foot lbs of torque does a 4 ½ hp saw that runs at 8000 rpm’s put out at the shaft?
Shaft Torque
- Thread starter Oregon_Rob
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kam
ArboristSite Operative
T(in-lb)=(63025XHP)/RPM=(63025X4.5)/8000
=35.45in-lb=2.95ft-lb
Is your saw 4.5HP at 8000 rpm? If not, this would not be accurate.
=35.45in-lb=2.95ft-lb
Is your saw 4.5HP at 8000 rpm? If not, this would not be accurate.
Oregon_Rob
ArboristSite Guru
Good question, I don’t know. I am playing with the idea of coming up with a home made chainsaw winch. Which brings me to my next question, how do the commercial chain saws achieve such a large reduction? I am thinking I would need about 250:1 reduction.
When it comes to winches, don't forget about the fact that the number of layers of cable you have on the spool makes a huge difference on the amount of pulling power you have. Since torque is equal to force times lever distance (moment arm), the effective diameter of the spool and cable get into the act. If the spool is full (many layers of cable), the winch will have less pulling power than if it's near emplty (cable reeled out so there is only one layer). Reciprocally, a full spool will move the cable quicker and a near empty spool will move it slower. At 250:1 ratio, most quality winches use a planetary reduction drive.
