Ultimately, the goal is to maximize the resolution of the current reading without missing any valuable data. With motors, the problem is that the starting current peak is 5 to 6 times higher than the normal current draw. This means that if you want to record the current peak, the normal operation current readings will be 5 times less accurate then they could have been if the current sensor selected would have been targeted at maximizing the accuracy of the normal operation current. Suppose that you have a 10 HP pump using about 10 Amps when operating normally.
If the goal is to maximize the accuracy under normal operation, then a current sensor 50% higher than the capacity of the pump would be ideal. If the goal is to record the peak, then a current sensor slightly higher than the maximum peak will do the job. MAID Labs current sensors have the following capacities: 5A, 15A, 75A, 150A, 300A and 1500A. Custom orders can be placed.