Have you ever wait at the spec of anenginein a clip and seen something like " this engine makes 300 British pound - feet oftorqueat 4,000 RPM , " and wondered how muchpowerthat was ? How much H.P. are we talking about here ? you could calculate how many fundament - pounds of HP this engine produces using a common equation :
The engine that gain 300 pound - ft of torsion at 4,000 rev make [ ( 300 x 4,000 ) / 5,252 ] 228 horsepower at 4,000 rev . But where does the number 5,252 occur from ?
To get from pound - substructure of torque to horsepower , you need to go through a few conversions . The telephone number 5,252 is the result of chunk several dissimilar conversion factors together into one telephone number .
First , 1 horsepower is determine as 550 foot - pound per second ( readHow Horsepower Worksto find out how they got that number ) . The units of torque are pound - feet . So to get from torque to H.P. , you demand the " per 2nd " condition . You get that by multiplying the torque by the locomotive engine speed .
But engine speed is normally concern to in revolutions per minute ( rev ) . Since we want a " per second , " we want to convert RPMs to " something per arcsecond . " The seconds are easy – we just divide by 60 to get from minutes to second . Now what we need is a dimensionless whole for revolutions : a rad . A rad is actually a ratio of the distance of an electric discharge part by the length of a spoke , so the units of distance cancel out and you ’re left with a dimensionless measuring stick .
you’re able to reckon of a rotation as a measure of an angle . One gyration is 360 degree of a rophy . Since the perimeter of a circle is ( 2 x pi x radius ) , there are 2 - sherlock rad in a revolution . To convert revolutions per minute to radians per second , you multiply revolutions per minute by ( 2 - pi/60 ) , which equals 0.10472 radian per second . This gives us the " per second base " we necessitate to calculate horsepower .
allow ’s put this all together . We need to get to H.P. , which is 550 foot - pounds per second , using torque ( pound - base ) and locomotive speed ( revolutions per minute ) . If we part the 550 foot - dog pound by the 0.10472 rad per second ( engine speed ) , we get 550/0.10472 , which equals 5,252 .
So if you procreate torque ( in pound - metrical unit ) by engine speed ( in RPM ) and fraction the product by 5,252 , RPM is commute to " radians per secondly " and you could get from torsion to HP – from " pound - feet " to " human foot - pound per second base . "
For related article on torque , horsepower and engine , check out out the links on the next Thomas Nelson Page .
