What is the real purpose about calculating Torque in a shaft??

Question

I mean, suppose I have a 300 HP motor and I have a shaft with 1 in of diameter and also 2000 rpm of spining motion. I know the Torque is 9450 lb*in. But with this value, what will I do then? What is it for? Can anyone tell me after of this then what in real application. ?

real answer 10 pts

Answer 1

Torque creates stress in the bar, use that to assess the possibility of failure or breaking. I bet different engineers have a million answers for this one.

Answer 2

In order to properly select a motor, it is necessary to consider the torque vs. speed capability curve of the motor in comparison to the torque vs. speed characteristic curve of the driven load. The intersection of the motor curve and the load curve is the steady state operating point. The excess capability torque above load torque at any given speed is the torque available to accelerate the load inertia to the steady state operating point. It may be necessary to calculate how long it takes for the motor to accelerate the load to the operating speed when starting. It may also be necessary to determine the reserve torque available at the operating speed and consider the speed variation that might result from a momentary overload.

Of course, selecting the motor shaft is part of motor design and selecting the input shaft of the load is part of the design of that machine. Motors are designed with a standard shaft that is large enough to safely transmit the motor's maximum torque. An over-sized shaft and bearings may be required if an unusually large force will be exerted by drive belts.

Answer 3

Sure.  Calculating actual torque allows you to analyze likelihood of failure for a given shaft size.  This will then allow you to increase or decrease shaft size to suit your requirements.  Since material = money, you'd want to use the shaft that is least expensive to produce and implement while also being safe.  Keep in mind that the smallest shaft may not necessarily be the cheapest to use since there may be additional costs associated with non-standard sizes of shafts, bearings, couplers, etc.