Let us say there is a constant load which is driven by a geared 3-phase ACIM (AC Induction Motor) of 5kW power rating. The mechanical load and its speed is constant.
If I would need to replace this ACIM motor and gear with a BLDC motor and gear so that it could drive the same load with same speed as before then would I need to use a BLDC motor of 5kW power or is it possible that a lower power BLDC motor will also be able to drive the same load with same speed? The reason I think that a lower power, say 3kW BLDC motor will also be able to drive the same load is that BLDC are more efficient but I am not sure if my understanding is correct or not.
If my mechanical load is same then is it possible that a different type of motor will have different electrical power to drive the same load with same speed?