If you are after a specific amount of torque and the motor says it supplies that amount of torque, it does it at the rated current. If you put in less current, you get less torque. If you buy a motor that puts out 2X (or 5X) the torque you actually need, then sure, you can put a lot less current through it. You probably pay more for a higher torque motor, it's likely larger and heavier, it may (or may not) be the best design approach.
Derating current is fine. There's nothing wrong with it as part of a rational design. When you do, that also drops the drive voltage required for a given level of performance. Half the current will always require half the voltage ....
Derating current is fine. There's nothing wrong with it as part of a rational design. When you do, that also drops the drive voltage required for a given level of performance. Half the current will always require half the voltage ....