How does the torque of a construction crane relate to the torque of a car?
In an automobile, you are looking for torque over a wide range of speeds and loads. A crane does not need to have a great deal of speed in terms of lifting an object but does need a great deal of torque. The result is an automobile needs much more horsepower to meet its goals while a crane can actually lift a huge load with a much smaller amount of horsepower. I personally can remember a lift on one of the construction projects I was field engineer on. The lift of 650,000 pounds was made with two 85 horsepower Ford gasoline engines and two industrial gear boxes.
Torque is force x distance. In a car, the torque is the force twisting the drive axles, and the distance is the radius of the driving wheels. It controls the rate of acceleration of the car. In a crane, the force is that provided by the winch cable, and the distance is the length of the jib. It controls the weight the crane can lift.
