I have used this AD628 IC on a product to detect current on a single motor application, and it works very well, with highly sensitive detection. In the case of 4 motors however, I am wondering about the PS design. The single motor design uses the sense resistor on the input to the motor driver. For 4 motors, it is not that simple. So I am considreing using four 4 amp transformers, 4 bridge rectifiers and caps, 4 variable regulators, and a sense resistor on each driver boards power in to detect current on each motor. Is this the best method to you guys to accomplish 4 motor detection?
http://www.analog.com/UploadedFiles/...eets/AD628.pdf