Perhaps the biggest misunderstanding when looking at a motor nameplate concerns the motor's horsepower rating. You should consider this the same as looking into a bucket. Each has a capacity. The motor's horsepower is an expression of the amount of work a motor can do WHEN THE LOAD ASKS FOR IT, not how much work it will shove into the load. Therefore the load current, and consequently the horsepower the motor develops, is determined by the load, not by the motor.
For example, if a pump's impeller is turned at 1750 rpm, it will require a specific amount of horsepower as shown on the pump curves. Let's assume those curves call for a 10HP motor. The load on the motor will be the same whether a 10HP or a 20HP motor is supplied. This, of course, ignores things like efficiency and no-load current which will have minor effects on the motor current. But, you won't get any more output from the pump or draw twice the current by using the larger motor.
So, consider this when you size your overload protection.