Posted by jack cain on Thursday, April 12, 2007 at 10:31:07 :
In Reply to: Great Info Jack, Thank You ntxt posted by Paul (in NY) on Thursday, April 12, 2007 at 08:19:08 :
I was attempting to explain but not doing the greatest job due to the influence of two Percosets which I had taken to try to dull the pain from the two root canals that I had yesterday afternoon.
I am sure that this has been covered in past forums, but as I have now had a good night's sleep and am at the keyboard, I will take the time to ramble, hopefully not incoherently.
Horse Power and Torque are directly related with horsepower being an expression of rate of work and torque being the amount of force applied.
HP and Torque are equivalent at 5252 RPM (a consequence of James Watts original definition of HP). If a motor or engine is said to produce 100HP at 5252RPM then by definition it must produce 100 Ft Lbs of torque as well. HP will always be larger than torque at RPMs in excess of 5252 RPMs and torque will always be larger than HP at RPMs less that 5252 RPMs.
The formula for deriving Horse Power is HP=(torque * RMP)/5252.
The formula for deriving torque is Torque=(HP*5252)/RPM
So if you know either HP and RPM you can derive Torque and if you know torque and RMP you can derive HP. RPM being the common element of the tri-partite relationship.
But I can't put it any better than David did when explaining the considerations needed when replacing an electric motor with either a gas or diesel.